Anti-garp antibody

ABSTRACT

The present invention relates to an antibody that binds to GARP and is useful as a therapeutic agent for a tumor, and a method for treating a tumor using the aforementioned antibody. It is an object of the present invention to provide an antibody, which inhibits the function of Treg in a tumor and is thereby used as a pharmaceutical product having therapeutic effects, a method for treating a tumor using the aforementioned antibody, and the like. An anti-GARP antibody that binds to GARP and exhibits inhibitory activity to Treg function and exhibits ADCC activity is obtained, and moreover a pharmaceutical composition for use in tumor therapy, comprising the aforementioned antibody, etc. is obtained.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. national stage application ofInternational Patent Application No. PCT/JP2016/078067, filed Sep. 23,2016, which claims the benefit of priority to Japanese PatentApplication No. 2015-187488, filed Sep. 24, 2015, the entireties ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an antibody that binds to GARP and isuseful as a therapeutic agent for a tumor, and a method for treating atumor using the aforementioned antibody.

BACKGROUND ART

Regulatory T cells (Treg) are the main causative cells inducing immunetolerance that is observed in the tumor area of cancer patients. That isto say, in cancer patients, groups of immune cells that intrinsicallywork to kill tumors are rendered into a state of immune suppression byactivated Treg in the tumor, and this leads to the malignant progressionof the tumor [Non Patent Literature 1].

Glycoprotein-A Repetitions Predominant (GARP) is a protein with asingle-pass transmembrane structure [Non Patent Literature 2], and thisprotein is expressed on the cell surface of activated Treg and forms acomplex with latent TGF-β (a precursor of TGF-β which is an importantmolecule for inducing immune tolerance) [Non Patent Literature 3].

As a result of the cell-cell interaction between Treg and target cellsto which the Treg induces immunosuppression, TGF-β is matured fromlatent TGF-β by GARP on the cell surface of Treg and secreted from Treg,and the immunosuppressive signals of TGF-β are directly transmitted tothe target cells [Non Patent Literature 4, 5]. It has been demonstratedthat the membrane-bound GARP expressed on the cell surface is necessaryfor such maturation of TGF-β [Non Patent Literature 5]. On the otherhand, it has also been demonstrated that soluble GARP that lacks atransmembrane region suppresses proliferation of CD4 positive T cellswhen it is directly added to the cell culture [Non Patent Literature 6].Thus, it cannot be ruled out that there is an immunosuppressivemechanism of GARP which does not require TGF-β maturation on the cellmembrane.

GARP is not only expressed by Treg from peripheral blood when they getactivated, but also in a clinical setting by tumor infiltrating T cellsat tumor sites of cancer patients [Non Patent Literature 7], by Tregexisting in ascites [Non Patent Literature 8], and also by Tregcirculating in the peripheral blood of cancer patients [Non PatentLiterature 9].

In a report investigating the effect of inhibition of GARP expression onthe function of Treg, siRNA-targeting GARP inhibited theimmunosuppressive function of Treg on the proliferative responses ofhelper T cells, but such an inhibitory effect was partial [Non PatentLiterature 10].

In another report, anti-GARP antibodies (MHG-8 and LHG-10) which hadbeen obtained for their abilities to inhibit TGF-β maturation inhibitedthe suppressive function of A1 cells, which is a Treg cell line [NonPatent Literature 11] established from hemochromatosis patients, on theproliferative responses of helper T cells [Patent Literature 1 and NonPatent Literature 12]. However, it is not known whether or not theaforementioned antibodies effectively exhibit such inhibitory effects onTreg in a tumor microenvironment, and to date, no anti-GARP antibodyhaving such effects has been reported so far. An antibody recognizingboth GARP and TGF-β is also known [Patent Literature 2].

It has been demonstrated that the excessive presence and the activationof Treg in patients having malaria and HIV infection exhibit acorrelation with the disease state [Non Patent Literatures 13 and 14],and that the removal of Treg resulted in remission of the disease statein murine models for the diseases [Non Patent Literatures 15 and 16].

CITATION LIST Patent Literature

-   Patent Literature 1: WO2015/015003-   Patent Literature 2: WO2016/125017

Non Patent Literature

-   Non Patent Literature: 1: Int J Cancer. 2010 Aug. 15; 127(4):    759-67.-   Non Patent Literature: 2: PLoS One. 2008; 3(7): e2705.-   Non Patent Literature: 3: Proc Natl Acad Sci USA. 2009; 106(32):    13445-50.-   Non Patent Literature: 4: Eur J Immunol. 2009; 39(12): 3315-22.-   Non Patent Literature: 5: Mol Biol Cell. 2012; 23(6): 1129-39.-   Non Patent Literature: 6: Blood. 2013; 122(7): 1182-91.-   Non Patent Literature: 7: Eur J Immunol. 2012 July; 42(7): 1876-85.-   Non Patent Literature: 8: Clin Immunol. 2013 October; 149(1):    97-110.-   Non Patent Literature: 9: Cancer Res. 2013; 73: 2435.-   Non Patent Literature: 10: Proc Natl Acad Sci USA. 2009 Aug. 11;    106(32): 13445-50.-   Non Patent Literature: 11: Eur J Immunol. 2009; 39(12): 869-82.-   Non Patent Literature: 12: Sci Transl Med. 2015 Apr. 22; 7(284)-   Non Patent Literature: 13: PLoS One. 2008 Apr. 30; 3(4): e2027.-   Non Patent Literature: 14: Clin Exp Immunol. 2014 June; 176(3):    401-9.-   Non Patent Literature: 15: J Immunol. 2012 Jun. 1; 188(11): 5467-77.-   Non Patent Literature: 16: PLoS Pathog. 2013; 9(12): e1003798.

SUMMARY OF INVENTION Technical Problem

It is an object of the present invention to provide an antibody, whichinhibits the function of Treg in a tumor and is thereby used as apharmaceutical product having therapeutic effects, a method for treatinga tumor using the aforementioned antibody, and the like.

Solution to Problem

The present inventors have conducted intensive studies directed towardsachieving the aforementioned object. As a result, the inventors havefound an antibody that specifically binds to GARP and exhibits anactivity of inhibiting the function of Treg via antibody-dependentcellular cytotoxicity, thereby completing the present invention.Specifically, the present invention includes the following aspects ofthe invention.

(1) An antibody having the following properties:(a) specifically binding to Glycoprotein-A Repetitions Predominant(GARP);(b) having an inhibitory activity to the immunosuppressive function ofregulatory T cells;(c) having antibody-dependent cellular cytotoxic (ADCC) activity; and(d) having in vivo antitumor activity.(2) The antibody according to the above (1), wherein the GARP is amolecule consisting of the amino acid sequence shown in SEQ ID NO: 1.(3) The antibody according to the above (1) or (2), which binds to:(a) amino acid sequence portions at amino acid positions 366 to 377, 407to 445 and 456 to 470 shown in SEQ ID NO: 1,(b) amino acid sequence portions at amino acid positions 54 to 112 and366 to 392 shown in SEQ ID NO: 1,(c) amino acid sequence portions at amino acid positions 352 to 392shown in SEQ ID NO: 1, or(d) amino acid sequence portions at amino acid positions 18 to 112 shownin SEQ ID NO: 1.(4) The antibody according to any one of the above (1) to (3), which hascompetitive inhibitory activity, for binding to GARP, against anantibody having:(a) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 2 and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 3,(b) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 4 and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 5,(c) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 25 and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 27, or(d) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 29 and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 31.(5) The antibody according to any one of the above (1) to (4), whereinthe tumor is a cancer.(6) The antibody according to the above (5), wherein the cancer is lungcancer, kidney cancer, urothelial cancer, colon cancer, prostate cancer,glioblastoma multiforme, ovarian cancer, pancreatic cancer, breastcancer, melanoma, liver cancer, bladder cancer, stomach cancer,esophageal cancer, or blood cancer.(7) The antibody according to any one of the above (1) to (6), whichhas:(a) CDRH1 consisting of the amino acid sequence at amino acid positions26 to 35 shown in SEQ ID NO: 2, CDRH2 consisting of the amino acidsequence at amino acid positions 50 to 66 shown in SEQ ID NO: 2 andCDRH3 consisting of the amino acid sequence at amino acid positions 99to 107 shown in SEQ ID NO: 2, and CDRL1 consisting of the amino acidsequence at amino acid positions 23 to 36 shown in SEQ ID NO: 3, CDRL2consisting of the amino acid sequence at amino acid positions 52 to 58shown in SEQ ID NO: 3 and CDRL3 consisting of the amino acid sequence atamino acid positions 91 to 101 shown in SEQ ID NO: 3,(b) CDRH1 consisting of the amino acid sequence at amino acid positions26 to 35 shown in SEQ ID NO: 4, CDRH2 consisting of the amino acidsequence at amino acid positions 50 to 66 shown in SEQ ID NO: 4 andCDRH3 consisting of the amino acid sequence at amino acid positions 99to 112 shown in SEQ ID NO: 4, and CDRL1 consisting of the amino acidsequence at amino acid positions 23 to 36 shown in SEQ ID NO: 5, CDRL2consisting of the amino acid sequence at amino acid positions 52 to 58shown in SEQ ID NO: 5 and CDRL3 consisting of the amino acid sequence atamino acid positions 91 to 100 shown in SEQ ID NO: 5,(c) CDRH1 consisting of the amino acid sequence at amino acid positions45 to 54 shown in SEQ ID NO: 25, CDRH2 consisting of the amino acidsequence at amino acid positions 69 to 78 shown in SEQ ID NO: 25 andCDRH3 consisting of the amino acid sequence at amino acid positions 118to 125 shown in SEQ ID NO: 25, and CDRL1 consisting of the amino acidsequence at amino acid positions 44 to 54 shown in SEQ ID NO: 27, CDRL2consisting of the amino acid sequence at amino acid positions 70 to 76shown in SEQ ID NO: 27 and CDRL3 consisting of the amino acid sequenceat amino acid positions 109 to 117 shown in SEQ ID NO: 27, or(d) CDRH1 consisting of the amino acid sequence at amino acid positions45 to 54 shown in SEQ ID NO: 29, CDRH2 consisting of the amino acidsequence at amino acid positions 69 to 77 shown in SEQ ID NO: 29 andCDRH3 consisting of the amino acid sequence at amino acid positions 117to 128 shown in SEQ ID NO: 29, and CDRL1 consisting of the amino acidsequence at amino acid positions 44 to 54 shown in SEQ ID NO: 31, CDRL2consisting of the amino acid sequence at amino acid positions 70 to 76shown in SEQ ID NO: 31 and CDRL3 consisting of the amino acid sequenceat amino acid positions 109 to 117 shown in SEQ ID NO: 31.(8) The antibody according to any one of the above (1) to (7), whichhas:(a) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 1 to 118 shown in SEQ ID NO: 2, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 1 to 112 shown in SEQ ID NO: 3,(b) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 1 to 123 shown in SEQ ID NO: 4, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 1 to 111 shown in SEQ ID NO: 5,(c) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 20 to 136 shown in SEQ ID NO: 25, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 21 to 129 shown in SEQ ID NO: 27, or(d) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 20 to 139 shown in SEQ ID NO: 29, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 21 to 129 shown in SEQ ID NO: 31.(9) The antibody according to any one of the above (1) to (8), whereinthe constant region is a human-derived constant region.(10) The antibody according to any one of the above (1) to (9), whichhas:(a) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 2, and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 3,(b) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 4, and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 5,(c) a heavy chain consisting of the amino acid sequence at amino acidpositions 20 to 466 shown in SEQ ID NO: 25, and a light chain consistingof the amino acid sequence at amino acid positions 21 to 234 shown inSEQ ID NO: 27, or(d) a heavy chain consisting of the amino acid sequence at amino acidpositions 20 to 469 shown in SEQ ID NO: 29, and a light chain consistingof the amino acid sequence at amino acid positions 21 to 234 shown inSEQ ID NO: 31.(11) The antibody according to any one of the above (1) to (10), whichis humanized.(12) The antibody according to the above (11), which has: a heavy chainvariable region consisting of an amino acid sequence selected from thegroup consisting of:(a) the amino acid sequence at amino acid positions 20 to 136 shown inSEQ ID NO: 33,(b) the amino acid sequence at amino acid positions 20 to 136 shown inSEQ ID NO: 35,(c) the amino acid sequence at amino acid positions 20 to 139 shown inSEQ ID NO: 41,(d) an amino acid sequence having homology of at least 95% or more tothe sequence of a framework region other than at each CDR sequence inthe sequences of (a) to (c), and(e) an amino acid sequence comprising a deletion, substitution oraddition of one or several amino acids in the sequence of a frameworkregion other than at each CDR sequence in the sequences of (a) to (c),and

a light chain variable region consisting of an amino acid sequenceselected from the group consisting of:

(f) the amino acid sequence at amino acid positions 21 to 129 shown inSEQ ID NO: 37,(g) the amino acid sequence at amino acid positions 21 to 129 shown inSEQ ID NO: 39,(h) the amino acid sequence at amino acid positions 21 to 129 shown inSEQ ID NO: 43,(i) an amino acid sequence having homology of at least 95% or more tothe sequence of a framework region other than at each CDR sequence inthe sequences of (f) to (h), and(j) an amino acid sequence comprising a deletion, substitution oraddition of one or several amino acids in the sequence of a frameworkregion other than at each CDR sequence in the sequences of (f) to (h).(13) The antibody according to the above (11) or (12), which has:(a) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 20 to 136 shown in SEQ ID NO: 33, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 21 to 129 shown in SEQ ID NO: 37,(b) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 20 to 136 shown in SEQ ID NO: 35, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 21 to 129 shown in SEQ ID NO: 39, or(c) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 21 to 139 shown in SEQ ID NO: 41, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 21 to 129 shown in SEQ ID NO: 43.(14) The antibody according to any one of the above (11) to (13), whichhas:(a) a heavy chain selected from the group consisting of a heavy chainhaving the amino acid sequence at amino acid positions 20 to 466 shownin SEQ ID NO: 33, a heavy chain having the amino acid sequence at aminoacid positions 20 to 466 shown in SEQ ID NO: 35, and a heavy chainhaving the amino acid sequence at amino acid positions 20 to 469 shownin SEQ ID NO: 41, and(b) a light chain selected from the group consisting of a light chainhaving the amino acid sequence at amino acid positions 21 to 234 shownin SEQ ID NO: 37, a light chain having the amino acid sequence at aminoacid positions 21 to 234 shown in SEQ ID NO: 39, and a light chainhaving the amino acid sequence at amino acid positions 21 to 234 shownin SEQ ID NO: 43.(15) The antibody according to any one of the above (11) to (14), whichhas:(a) a heavy chain having the amino acid sequence at amino acid positions20 to 466 shown in SEQ ID NO: 33, and a light chain having the aminoacid sequence at amino acid positions 21 to 234 shown in SEQ ID NO: 37,(b) a heavy chain having the amino acid sequence at amino acid positions20 to 466 shown in SEQ ID NO: 35, and a light chain having the aminoacid sequence at amino acid positions 21 to 234 shown in SEQ ID NO: 39,or(c) a heavy chain having the amino acid sequence at amino acid positions20 to 469 shown in SEQ ID NO: 41, and a light chain having the aminoacid sequence at amino acid positions 21 to 234 shown in SEQ ID NO: 43.(16) A polynucleotide encoding the antibody according to any one of theabove (1) to (15).(17) The polynucleotide according to the above (16), which has:(a) a polynucleotide of CDRH1 consisting of the nucleotide sequence atnucleotide positions 76 to 105 shown in SEQ ID NO: 6, a polynucleotideof CDRH2 consisting of the nucleotide sequence at nucleotide positions148 to 198 shown in SEQ ID NO: 6 and a polynucleotide of CDRH3consisting of the nucleotide sequence at nucleotide positions 295 to 321shown in SEQ ID NO: 6, and a polynucleotide of CDRL1 consisting of thenucleotide sequence at nucleotide positions 67 to 108 shown in SEQ IDNO: 7, a polynucleotide of CDRL2 consisting of the nucleotide sequenceat nucleotide positions 154 to 174 shown in SEQ ID NO: 7 and apolynucleotide of CDRL3 consisting of the nucleotide sequence atnucleotide positions 271 to 303 shown in SEQ ID NO: 7,(b) a polynucleotide encoding CDRH1 consisting of the nucleotidesequence at nucleotide positions 76 to 105 shown in SEQ ID NO: 8, apolynucleotide of CDRH2 consisting of the nucleotide sequence atnucleotide positions 148 to 198 shown in SEQ ID NO: 8 and apolynucleotide of CDRH3 consisting of the nucleotide sequence atnucleotide positions 295 to 336 shown in SEQ ID NO: 8, and apolynucleotide of CDRL1 consisting of the nucleotide sequence atnucleotide positions 67 to 108 shown in SEQ ID NO: 9, a polynucleotideof CDRL2 consisting of the nucleotide sequence at nucleotide positions154 to 174 shown in SEQ ID NO: 9 and a polynucleotide of CDRL3consisting of the nucleotide sequence at nucleotide positions 271 to 300shown in SEQ ID NO: 9,(c) a polynucleotide of CDRH1 consisting of the nucleotide sequence atnucleotide positions 133 to 162 shown in SEQ ID NO: 24, a polynucleotideof CDRH2 consisting of the nucleotide sequence at nucleotide positions205 to 234 shown in SEQ ID NO: 24 and a polynucleotide of CDRH3consisting of the nucleotide sequence at nucleotide positions 352 to 375shown in SEQ ID NO: 24, and a polynucleotide of CDRL1 consisting of thenucleotide sequence at nucleotide positions 130 to 162 shown in SEQ IDNO: 26, a polynucleotide of CDRL2 consisting of the nucleotide sequenceat nucleotide positions 208 to 228 shown in SEQ ID NO: 26 and apolynucleotide of CDRL3 consisting of the nucleotide sequence atnucleotide positions 325 to 351 shown in SEQ ID NO: 26, or(d) a polynucleotide of CDRH1 consisting of the nucleotide sequence atnucleotide positions 133 to 162 shown in SEQ ID NO: 28, a polynucleotideof CDRH2 consisting of the nucleotide sequence at nucleotide positions205 to 231 shown in SEQ ID NO: 28 and a polynucleotide of CDRH3consisting of the nucleotide sequence at nucleotide positions 349 to 384shown in SEQ ID NO: 28, and a polynucleotide of CDRL1 consisting of thenucleotide sequence at nucleotide positions 130 to 162 shown in SEQ IDNO: 30, a polynucleotide of CDRL2 consisting of the nucleotide sequenceat nucleotide positions 208 to 228 shown in SEQ ID NO: 30 and apolynucleotide of CDRL3 consisting of the nucleotide sequence atnucleotide positions 325 to 351 shown in SEQ ID NO: 30.(18) The polynucleotide according to the above (16) or (17), which has:(a) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 1 to 354 shown in SEQ ID NO:6, and a polynucleotide of a light chain variable region consisting ofthe nucleotide sequence at nucleotide positions 1 to 336 shown in SEQ IDNO: 7,(b) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 1 to 369 shown in SEQ ID NO:8, and a polynucleotide of a light chain variable region consisting ofthe nucleotide sequence at nucleotide positions 1 to 333 shown in SEQ IDNO: 9,(c) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 24, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 26, or(d) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 417 shown in SEQ IDNO: 28, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 30.(19) The polynucleotide according to any one of the above (16) to (18),which has:(a) a polynucleotide of a heavy chain consisting of the nucleotidesequence shown in SEQ ID NO: 6, and a polynucleotide of a light chainconsisting of the nucleotide sequence shown in SEQ ID NO: 7,(b) a polynucleotide of a heavy chain consisting of the nucleotidesequence shown in SEQ ID NO: 8, and a polynucleotide of a light chainconsisting of the nucleotide sequence shown in SEQ ID NO: 9,(c) a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1398 shown in SEQ ID NO: 24, anda polynucleotide of a light chain consisting of the nucleotide sequenceat nucleotide positions 61 to 702 shown in SEQ ID NO: 26, or(d) a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1407 shown in SEQ ID NO: 28, anda polynucleotide of a light chain consisting of the nucleotide sequenceat nucleotide positions 61 to 702 shown in SEQ ID NO: 30.(20) The polynucleotide according to the above (16) or (17), which has:(a) a polynucleotide of a heavy chain variable region selected from thegroup consisting of a polynucleotide of a heavy chain variable regionconsisting of the nucleotide sequence at nucleotide positions 58 to 408shown in SEQ ID NO: 32, a polynucleotide of a heavy chain variableregion consisting of the nucleotide sequence at nucleotide positions 58to 408 shown in SEQ ID NO: 34, and a polynucleotide of a heavy chainvariable region consisting of the nucleotide sequence at nucleotidepositions 58 to 417 shown in SEQ ID NO: 40, and(b) a polynucleotide of a light chain variable region selected from thegroup consisting of a polynucleotide of a light chain variable regionconsisting of the nucleotide sequence at nucleotide positions 61 to 387shown in SEQ ID NO: 36, a polynucleotide of a light chain variableregion consisting of the nucleotide sequence at nucleotide positions 61to 387 shown in SEQ ID NO: 38, and a polynucleotide of a light chainvariable region consisting of the nucleotide sequence at nucleotidepositions 61 to 387 shown in SEQ ID NO: 42.(21) The polynucleotide according to the above (16), (17) or (20), whichhas:(a) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 32, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 36,(b) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 34, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 38, or(c) a polynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 417 shown in SEQ IDNO: 40, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 42.(22) The polynucleotide according to the above (16), (17), (20) or (21),which has:(a) a polynucleotide of a heavy chain selected from the group consistingof a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1398 shown in SEQ ID NO: 32, apolynucleotide of a heavy chain consisting of the nucleotide sequence atnucleotide positions 58 to 1398 shown in SEQ ID NO: 34, and apolynucleotide of a heavy chain consisting of the nucleotide sequence atnucleotide positions 58 to 1407 shown in SEQ ID NO: 40, and(b) a polynucleotide of a light chain selected from the group consistingof a polynucleotide of a light chain consisting of the nucleotidesequence at nucleotide positions 61 to 702 shown in SEQ ID NO: 36, apolynucleotide of a light chain consisting of the nucleotide sequence atnucleotide positions 61 to 702 shown in SEQ ID NO: 38, and apolynucleotide of a light chain consisting of the nucleotide sequence atnucleotide positions 61 to 702 shown in SEQ ID NO: 42.(23) The polynucleotide according to any one of the above (16), (17) and(20) to (22), which has:(a) a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1398 shown in SEQ ID NO: 32, anda polynucleotide of a light chain consisting of the nucleotide sequenceat nucleotide positions 61 to 702 shown in SEQ ID NO: 36,(b) a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1398 shown in SEQ ID NO: 34, anda polynucleotide of a light chain consisting of the nucleotide sequenceat nucleotide positions 61 to 702 shown in SEQ ID NO: 38, or(c) a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1407 shown in SEQ ID NO: 40, anda polynucleotide of a light chain consisting of the nucleotide sequenceat nucleotide positions 61 to 702 shown in SEQ ID NO: 42.(24) An expression vector comprising the polynucleotide according to anyone of the above (16) to (23).(25) Host cells transformed with the expression vector according to theabove (24).(26) A method for producing an antibody of interest or a fragmentthereof, which comprises a step of culturing the host cells according tothe above (25), and a step of collecting an antibody of interest fromthe culture obtained by the aforementioned step.(27) An antibody obtained by the production method according to theabove (26).(28) The antibody according to any one of the above (1) to (15) and(27), comprising one or two or more modifications selected from thegroup consisting of N-linked glycosylation, O-linked glycosylation,N-terminal processing, C-terminal processing, deamidation, isomerizationof aspartic acid, oxidation of methionine, addition of a methionineresidue to the N-terminus, amidation of a proline residue, and a heavychain comprising a deletion of one or two amino acids at the carboxylterminus.(29) The antibody according to the above (28), wherein one or two aminoacids are deleted at the carboxyl terminus of a heavy chain thereof.(30) The antibody according to the above (29), wherein one amino acid isdeleted at each of the carboxyl termini of both of the heavy chainsthereof.(31) The antibody according to any one of the above (28) to (30),wherein a proline residue at the carboxyl terminus of a heavy chainthereof is further amidated.(32) The antibody according to any one of the above (1) to (15) and (27)to (31), wherein sugar chain modification is regulated in order toenhance antibody-dependent cellular cytotoxicity.(33) A pharmaceutical composition comprising at least one of theantibodies according to the above (1) to (15) and (27) to (32).(34) The pharmaceutical composition according to the above (33), whichis for use in tumor therapy.(35) The pharmaceutical composition according to the above (34), whereinthe tumor is a cancer.(36) The pharmaceutical composition according to the above (35), whereinthe cancer is lung cancer, kidney cancer, urothelial cancer, coloncancer, prostate cancer, glioblastoma multiforme, ovarian cancer,pancreatic cancer, breast cancer, melanoma, liver cancer, bladdercancer, stomach cancer, esophageal cancer, or blood cancer.(37) A method for treating a tumor, which comprises administering atleast one of the antibodies according to the above (1) to (15) and (27)to (32) to an individual.(38) The treatment method according to the above (37), wherein the tumoris a cancer.(39) The treatment method according to the above (38), wherein thecancer is lung cancer, kidney cancer, urothelial cancer, colon cancer,prostate cancer, glioblastoma multiforme, ovarian cancer, pancreaticcancer, breast cancer, melanoma, liver cancer, bladder cancer, stomachcancer, esophageal cancer, or blood cancer.

Advantageous Effects of Invention

According to the present invention, there can be obtained a therapeuticagent for cancer comprising an antibody binding to GARP and having anantitumor activity caused by ADCC-mediated inhibition of Treg. Inaddition, the excessive presence and the activation of Treg in patientshaving malaria and HIV infection exhibit a correlation with that diseasestate, and the removal of Treg induces remission of the disease state inmurine models for the diseases. Accordingly, it can be expected thateffective inhibition of Treg function will have therapeutic effects alsoon refractory infectious diseases such as those caused by malaria andHIV.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the amino acid sequence (SEQ ID NO: 1) of GARP.

FIG. 2 shows the amino acid sequence (SEQ ID NO: 2) of a 105F antibodyheavy chain.

FIG. 3 shows the amino acid sequence (SEQ ID NO: 3) of a 105F antibodylight chain.

FIG. 4 shows the amino acid sequence (SEQ ID NO: 4) of a 110F antibodyheavy chain.

FIG. 5 shows the amino acid sequence (SEQ ID NO: 5) of a 110F antibodylight chain.

FIG. 6 shows the nucleotide sequence (SEQ ID NO: 6) of a 105F antibodyheavy chain.

FIG. 7 shows the nucleotide sequence (SEQ ID NO: 7) of a 105F antibodylight chain.

FIG. 8 shows the nucleotide sequence (SEQ ID NO: 8) of a 110F antibodyheavy chain.

FIG. 9 shows the nucleotide sequence (SEQ ID NO: 9) of a 110F antibodylight chain.

FIG. 10 shows the binding of antibodies to GARP. The 105F antibody andthe 110F antibody exhibited the binding thereof to GARP according to anELISA method.

FIG. 11 shows the specific binding of antibodies to GARP. The 105Fantibody did not bind to HEK293T cells, into which an empty vector hadbeen introduced, and exhibited the binding thereof to HEK293T cells, inwhich GARP had been transiently expressed.

FIG. 12 shows the specific binding of an antibody to GARP. The 105Fantibody exhibited a binding activity to L428 cells endogenouslyexpressing GARP.

FIG. 13 shows the specific binding of antibodies to GARP. The 105Fantibody exhibited a binding activity to activated Treg.

FIG. 14 shows the ADCC activity of antibodies. When L428 cellsendogenously expressing GARP were targeted, an increase in the ADCCactivity was found in a 105F antibody concentration-dependent manner.

FIG. 15 shows the inhibitory activity of an antibody to the Tregfunction. The 105F antibody (50 μg/mL) inhibited theproliferation-suppressive function of Treg against helper T cells.

FIG. 16 shows the inhibitory activity of antibody to the Treg function.The 105F antibody (10 μg/mL) inhibited the proliferation-suppressivefunction of Treg against helper T cells. On the other hand, the MHG-8and LHG-10 antibodies did not exhibit the effect on theproliferation-suppressive function of Treg against helper T cells.

FIG. 17 shows the amino acid sequence (SEQ ID NO: 25) of a c151Dantibody heavy chain.

FIG. 18 shows the amino acid sequence (SEQ ID NO: 27) of a c151Dantibody light chain.

FIG. 19 shows the amino acid sequence (SEQ ID NO: 29) of a c198Dantibody heavy chain.

FIG. 20 shows the amino acid sequence (SEQ ID NO: 31) of a c198Dantibody light chain.

FIG. 21 shows the amino acid sequence (SEQ ID NO: 33) of an h151D-H1heavy chain.

FIG. 22 shows the amino acid sequence (SEQ ID NO: 37) of an h151D-L1light chain.

FIG. 23 shows the amino acid sequence (SEQ ID NO: 35) of an h151D-H4heavy chain.

FIG. 24 shows the amino acid sequence (SEQ ID NO: 39) of an h151D-L4light chain.

FIG. 25 shows the amino acid sequence (SEQ ID NO: 41) of an h198D-H3heavy chain.

FIG. 26 shows the amino acid sequence (SEQ ID NO: 43) of an h198D-L4light chain.

FIG. 27 shows the nucleotide sequence (SEQ ID NO: 24) of a c151Dantibody heavy chain.

FIG. 28 shows the nucleotide sequence (SEQ ID NO: 26) of a c151Dantibody light chain.

FIG. 29 shows the nucleotide sequence (SEQ ID NO: 28) of a c198Dantibody heavy chain.

FIG. 30 shows the nucleotide sequence (SEQ ID NO: 30) of a c198Dantibody light chain.

FIG. 31 shows the nucleotide sequence (SEQ ID NO: 32) of a h151D-H1antibody heavy chain.

FIG. 32 shows the nucleotide sequence (SEQ ID NO: 36) of a h151D-L1antibody heavy chain.

FIG. 33 shows the nucleotide sequence (SEQ ID NO: 34) of an h151D-H4heavy chain.

FIG. 34 shows the nucleotide sequence (SEQ ID NO: 38) of an h151D-L4light chain.

FIG. 35 shows the nucleotide sequence (SEQ ID NO: 40) of an h198D-H3heavy chain.

FIG. 36 shows the nucleotide sequence (SEQ ID NO: 42) of an h198D-L4light chain.

FIG. 37 shows the binding activity of each antibody to GARP-expressingcells. h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibited a specificbinding activity to GARP.

FIG. 38 shows the binding activity of each antibody to GARP-TGF β1co-expressing cells. Individual antibodies 105F, h151D-H1L1, h151D-H4L4and h198D-H3L4 bound to both GARP and a GARP mutant, which wereco-expressed with TGFβ1, and these antibodies exhibited a bindingactivity to a different region in GARP from the case of known antibodiesMHG8 and LHG10.

FIG. 39 shows the binding activity of each antibody to L428 cells.Individual antibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibited abinding activity to endogenously expressed GARP.

FIG. 40 shows the binding activity of each antibody to Treg. Individualantibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibited a bindingactivity to FoxP3-positive Treg.

FIG. 41 shows the ADCC activity of each antibody. Individual antibodiesh151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibited an ADCC activity.

FIG. 42 shows inhibitory activity of each antibody to the Treg function.Individual antibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibitedinhibitory activity to the Treg function.

FIG. 43 shows suppressive activity of Treg on the target cell lysisactivity of CTL.

FIG. 44 shows an increase in antitumor activity of each antibody.Individual antibodies 105F, h151D-H1L1, h151D-H4L4, and h198D-H3L4inhibited the suppressive function of Treg on cell lysis activity ofCTL.

FIG. 45 shows the in vivo antitumor activity of each antibody.Individual antibodies 105F, h151D-H1L1, h151D-H4L4, and h198D-H3L4exhibited an antitumor activity in in vivo models.

DESCRIPTION OF EMBODIMENTS

In the present description, the term “cancer” is used to have the samemeaning as that of the term “tumor”.

In the present description, the term “gene” is used to include, not onlyDNA but also its mRNA and cDNA, and the cRNA thereof.

In the present description, the term “polynucleotide” is used to havethe same meaning as that of a nucleic acid, and it includes DNA, RNA, aprobe, an oligonucleotide, and a primer.

In the present description, the term “polypeptide” is used such that itis not distinguished from the term “protein.”

In the present description, the term “cell” includes cells in anindividual animal, and cultured cells.

In the present description, the term “GARP” is used to have the samemeaning as that of GARP protein.

In the present description, the term “cytotoxicity” is used to mean thata pathologic change is caused to cells in any given way. It does notonly mean a direct trauma, but also means all types of structural orfunctional damage caused to cells, such as DNA cleavage, formation of abase dimer, chromosomal cleavage, damage to cell mitotic apparatus, anda reduction in the activities of various types of enzymes.

In the present description, the term “cytotoxic activity” is used tomean an activity that causes the above described cytotoxicity.

In the present description, the term “antibody-dependent cellularcytotoxicity” is used to mean an “antibody dependent cellular cytotoxic(ADCC) activity,” and this activity means the effect or the activity ofdamaging target cells such as tumor cells by NK cells mediated by anantibody.

In the present description, the term “epitope” is used to mean thepartial peptide or partial three-dimensional structure of GARP, to whicha specific anti-GARP antibody binds. Such an epitope, which is a partialpeptide of the above described GARP, can be determined by a method wellknown to a person skilled in the art, such as an immunoassay, forexample, by the following method. First, various partial structures ofan antigen are produced. As regards production of such partialstructures, a known oligopeptide synthesis technique can be applied. Forexample, a series of peptides, in which an antigen has been successivelytruncated at an appropriate length from the C-terminus or N-terminusthereof, are produced by a genetic recombination technique well known toa person skilled in the art, and thereafter, the reactivity of anantibody to such polypeptides is studied, and recognition sites areroughly determined. Thereafter, further shorter peptides aresynthesized, and the reactivity thereof to the aforementioned peptidesis then studied, so as to determine an epitope. Moreover, an epitope,which is a partial three-dimensional structure of an antigen that bindsto a specific antibody, can be determined by specifying the amino acidresidues of an antigen adjacent to the above-described antibody by X-raystructural analysis.

In the present description, the phrase “antibodies binding to the sameepitope” is used to mean different antibodies that bind to a commonepitope. If a second antibody binds to a partial peptide or a partialthree-dimensional structure, to which a first antibody binds, it can bedetermined that the first antibody and the second antibody bind to thesame epitope. In addition, by confirming that a second antibody competeswith a first antibody for the binding of a first antibody to an antigen(i.e., a second antibody interferes with the binding of a first antibodyto an antigen), it can be determined that the first antibody and thesecond antibody bind to the same epitope, even if the specific sequenceor structure of the epitope has not been determined. Furthermore, when afirst antibody and a second antibody bind to the same epitope andfurther, the first antibody has special effects such as antitumoractivity, the second antibody can be expected to have the same activityas that of the first antibody. Accordingly, if a second anti-GARPantibody binds to a partial peptide to which a first anti-GARP antibodybinds, it can be determined that the first antibody and the secondantibody bind to the same epitope of GARP. In addition, by confirmingthat the second anti-GARP antibody competes with the first anti-GARPantibody for the binding of the first anti-GARP antibody to GARP, it canbe determined that the first antibody and the second antibody areantibodies binding to the same epitope of GARP.

In the present description, the term “CDR” is used to mean acomplementarity determining region. It is known that the heavy chain andlight chain of an antibody molecule each have three CDRs. Such a CDR isalso referred to as a hypervariable domain, and is located in thevariable region of the heavy chain and light chain of an antibody. Theseregions have a particularly highly variable primary structure and areseparated into three sites on the primary structure of the polypeptidechain in each of the heavy chain and light chain. In the presentdescription, with regard to the CDR of an antibody, the CDRs of a heavychain are referred to as CDRH1, CDRH2 and CDRH3, respectively, from theamino-terminal side of the amino acid sequence of the heavy chain,whereas the CDRs of a light chain are referred to as CDRL1, CDRL2 andCDRL3, respectively, from the amino-terminal side of the amino acidsequence of the light chain. These sites are located close to oneanother on the three-dimensional structure, and determine thespecificity of the antibody to an antigen, to which the antibody binds.

In the present invention, the phrase “to hybridize under stringentconditions” is used to mean that hybridization is carried out in thecommercially available hybridization solution ExpressHyb HybridizationSolution (manufactured by Clontech) at 68° C., or that hybridization iscarried out under conditions in which hybridization is carried out usinga DNA-immobilized filter in the presence of 0.7-1.0 M NaCl at 68° C.,and the resultant is then washed at 68° C. with a 0.1- to 2-foldconcentration of SSC solution (wherein 1×SSC consists of 150 mM NaCl and15 mM sodium citrate) for identification, or conditions equivalentthereto.

1. GARP

GARP used in the present invention can be directly purified from theGARP-expressing cells of a human or a non-human mammal (e.g., a rat, amouse, etc.) and can then be used, or a cell membrane faction of theaforementioned cells can be prepared and can be used as the GARP.Alternatively, GARP can also be obtained by synthesizing it in vitro, orby allowing host cells to produce GARP by genetic manipulation.According to such genetic manipulation, the GARP protein can beobtained, specifically, by incorporating GARP cDNA into an expressionvector capable of expressing the GARP cDNA, and then synthesizing GARPin a solution comprising enzymes, substrate and energetic materialsnecessary for transcription and translation, or by transforming the hostcells of other prokaryotes or eukaryotes, so as to allow them to expressGARP.

The amino acid sequence of human GARP is shown in SEQ ID NO: 1 in thesequence listing. In addition, the sequence of SEQ ID NO: 1 is shown inFIG. 1.

Moreover, a protein, which consists of an amino acid sequence comprisinga substitution, deletion and/or addition of one or several amino acidsin the above-described amino acid sequence of GARP, and has a biologicalactivity equivalent to that of the GARP protein, is also included inGARP.

Mature human GARP, from which a signal sequence has been removed,corresponds to an amino acid sequence consisting of the amino acidresidues at positions 20 to 662 in the amino acid sequence shown in SEQID NO: 1.

Furthermore, a protein, which consists of an amino acid sequencecomprising a substitution, deletion and/or addition of one or severalamino acids in the amino acid sequence shown in SEQ ID NO: 1, or in theamino acid sequence shown in SEQ ID NO: 1 from which a signal sequencehas been removed, and which has a biological activity equivalent to thatof GARP, is also included in GARP. Further, a protein, which consists ofan amino acid sequence encoded by a splicing variant transcribed from ahuman GARP gene locus or an amino acid sequence comprising asubstitution, deletion and/or addition of one or several amino acids inthe aforementioned amino acid sequence, and which has a biologicalactivity equivalent to that of GARP, is also included in GARP.

2. Production of Anti-GARP Antibody

An example of the antibody against GARP of the present invention can bean anti-GARP human antibody. The anti-GARP human antibody means a humanantibody having only the gene sequence of an antibody derived from humanchromosomes.

The anti-GARP human antibody can be obtained by a method using a humanantibody-producing mouse having a human chromosomal fragment comprisingthe heavy chain and light chain genes of a human antibody (see Tomizuka,K. et al., Nature Genetics (1997) 16, p. 133-143; Kuroiwa, Y. et al.,Nucl. Acids Res. (1998) 26, p. 3447-3448; Yoshida, H. et al., AnimalCell Technology: Basic and Applied Aspects vol. 10, p. 69-73 (Kitagawa,Y., Matsuda, T. and Iijima, S. eds.), Kluwer Academic Publishers, 1999;Tomizuka, K. et al., Proc. Natl. Acad. Sci. USA (2000) 97, p. 722-727;etc.).

Such a human antibody-producing mouse can be specifically produced byusing a genetically modified animal, the gene loci of endogenousimmunoglobulin heavy chain and light chain of which have been disruptedand instead the gene loci of human immunoglobulin heavy chain and lightchain have been then introduced using a yeast artificial chromosome(YAC) vector or the like, and then producing a knock-out animal and atransgenic animal from such a genetically modified animal, and thenbreeding such animals with one another.

Otherwise, the anti-GARP human antibody can also be obtained bytransforming eukaryotic cells with cDNA encoding each of the heavy chainand light chain of such a human antibody, or preferably with a vectorcomprising the cDNA, according to genetic recombination techniques, andthen culturing the transformed cells producing a genetically modifiedhuman monoclonal antibody, so that the antibody can be obtained from theculture supernatant. As host cells, eukaryotic cells, and preferably,mammalian cells such as CHO cells, lymphocytes or myelomas can, forexample, be used.

Alternatively, the antibody can also be obtained by a method ofobtaining a phage display-derived human antibody that has been selectedfrom a human antibody library (see Wormstone, I. M. et al.,Investigative Ophthalmology & Visual Science. (2002) 43 (7), p.2301-2308; Carmen, S. et al., Briefings in Functional Genomics andProteomics (2002), 1 (2), p. 189-203; Siriwardena, D. et al.,Ophthalmology (2002) 109 (3), p. 427-431; etc.). For example, a phagedisplay method, which comprises allowing the variable region of a humanantibody to express as a single chain antibody (scFv) on the surface ofa phage, and then selecting a phage binding to an antigen, can beapplied (Nature Biotechnology (2005), 23, (9), p. 1105-1116).

By analyzing the phage gene that has been selected because of itsbinding ability to the antigen, a DNA sequence encoding the variableregion of a human antibody binding to the antigen can be determined.Once the DNA sequence of scFv binding to the antigen is determined, aDNA sequence of a constant region of an antibody is allowed to bindthereto to produce an IgG expression vector having the aforementionedsequences, and the produced expression vector is then introduced intosuitable host cells and is allowed to express therein, thereby obtaininga human antibody (WO92/01047, WO92/20791, WO93/06213, WO93/11236,WO93/19172, WO95/01438, WO95/15388, Annu. Rev. Immunol (1994) 12, p.433-455, Nature Biotechnology (2005) 23 (9), p. 1105-1116).

Moreover, the antibody against GARP of the present invention can beobtained by immunizing an animal with GARP or any given polypeptideselected from the amino acid sequence of GARP, and then collecting andpurifying an antibody produced in a living body thereof. The species ofthe organism of the GARP used as an antigen is not limited to human, andthus, an animal can also be immunized with GARP derived from an animalother than a human, such as a mouse or a rat. In this case, an antibodyapplicable to the disease of a human can be selected by examining thecross-reactivity of the obtained antibody binding to heterologous GARPwith human GARP.

Furthermore, antibody-producing cells that produce an antibody againstGARP are fused with myeloma cells according to a known method (e.g.,Kohler and Milstein, Nature (1975) 256, p. 495-497, Kennet, R. ed.,Monoclonal Antibodies, p. 365-367, Plenum Press, N.Y. (1980)) toestablish hybridomas, so as to obtain a monoclonal antibody.

It is to be noted that GARP used as an antigen can be obtained byallowing host cells to produce GARP genes according to geneticmanipulation.

Specifically, a vector capable of expressing a GARP gene is produced,and the vector is then introduced into host cells, so that the gene isexpressed therein, and thereafter, the expressed GARP may be purified.Hereafter, a method of obtaining an antibody against GARP will bespecifically described.

(1) Preparation of Antigen Examples of an antigen used to produce ananti-GARP antibody can include GARP, a polypeptide consisting of atleast 6 consecutive partial amino acid sequences thereof, and aderivative prepared by adding any given amino acid sequence or carrierto such GARP or a polypeptide thereof.

GARP can be directly purified from the tumor tissues or tumor cells of ahuman and can then be used. Alternatively, GARP can also be obtained bysynthesizing it in vitro or by allowing host cells to produce it bygenetic manipulation.

According to such genetic manipulation, an antigen can be obtained,specifically, by incorporating GARP cDNA into an expression vectorcapable of expressing the GARP cDNA, and then synthesizing GARP in asolution comprising enzymes, substrate and energetic materials necessaryfor transcription and translation, or by transforming the host cells ofother prokaryotes or eukaryotes, so as to allow them to express GARP.

It is also possible to obtain an antigen as a secretory protein byallowing a fusion protein formed by ligating DNA encoding theextracellular region of GARP as a membrane protein to DNA encoding theconstant region of an antibody, to express in a suitable host and/orvector system.

GARP cDNA can be obtained by what is called a PCR method, whichcomprises performing a polymerase chain reaction (hereinafter referredto as “PCR”), for example, using a cDNA library expressing the cDNA ofGARP as a template, and also using primers for specifically amplifyingthe GARP cDNA (see Saiki, R. K., et al. Science (1988) 239, p. 487-489).

An example of the in vitro synthesis of a polypeptide can be the RapidTranslation System (RTS) manufactured by Roche Diagnostics, but it isnot limited thereto.

Examples of prokaryotic cells used as host cells can include Escherichiacoli and Bacillus subtilis. In order to transform the host cells with agene of interest, the host cells are transformed with a plasmid vectorcomprising a replicon derived from species compatible with the host,namely, a replication origin, and a regulatory sequence. As a vector, avector having a sequence capable of imparting the selectivity of aphenotype to the cells to be transformed is preferable.

Examples of eukaryotic cells used as host cells can include the cells ofvertebrate, insects and yeasts. Examples of the vertebrate cells thatcan frequently be used include COS cells which are monkey cells(Gluzman, Y., Cell (1981) 23, p. 175-182, ATCC CRL-1650), mousefibroblasts NIH3T3 (ATCC No. CRL-1658), and a dihydrofolatereductase-deficient cell line of Chinese hamster ovary cells (CHO cells,ATCC CCL-61) (Urlaub, G. and Chasin, L. A. Proc. Natl. Acad. Sci. U.S.A.(1980) 77, p. 4126-4220), but are not limited thereto.

The thus obtained transformant can be cultured according to ordinarymethods, and a polypeptide of interest can be produced inside or outsideof the cells of the culture.

As media used in the culture, various types of commonly used media canbe selected, as appropriate, depending on the type of the adopted hostcells. If the host cells are Escherichia coli, for example, antibioticssuch as ampicillin or IPMG can be added to an LB medium, as necessary,and the resulting medium can then be used.

A recombinant protein produced inside or outside of the cells of atransformant as a result of the above described culture can be separatedand/or purified by various types of known separation methods, utilizingthe physical properties or chemical properties of the protein.

Specific examples of the method can include a treatment using anordinary protein precipitant, ultrafiltration, various types of liquidchromatography such as molecular sieve chromatography (gel filtration),absorption chromatography, ion exchange chromatography or affinitychromatography, a dialysis method, and a combination thereof.

In addition, by attaching a histidine tag consisting of 6 residues to arecombinant protein to be expressed, the protein can be efficientlypurified using a nickel affinity column. Otherwise, by connecting the Fcregion of IgG to a recombinant protein to be expressed, the protein canbe efficiently purified using a Protein A column.

By combining the above described methods with one another, a polypeptideof interest can be produced at a large scale, with a high yield and withhigh purity.

(2) Production of Anti-GARP Monoclonal Antibody

An example of an antibody specifically binding to GARP can be amonoclonal antibody specifically binding to GARP. A method of obtainingsuch a monoclonal antibody is as follows.

For the production of a monoclonal antibody, the following working stepsare generally necessary.

Specifically, the necessary working steps include:

(a) purification of a biopolymer used as an antigen,(b) a step of immunizing an animal with the antigen by injection,collecting the blood from the animal, examining the antibody titer todetermine the period for excision of the spleen from the animal, andthen preparing antibody-producing cells,(c) preparation of myeloma cells (hereinafter referred to as“myelomas”),(d) cell fusion between the antibody-producing cells and the myelomas,(e) selection of a hybridoma group producing an antibody of interest,(f) division into single cell clones (cloning),(g) optionally, the culture of hybridomas for the mass production ofmonoclonal antibodies, or the breeding of animals into which thehybridomas are transplanted, and(h) the analysis of the physiological activity and binding specificityof the thus produced monoclonal antibody, or examination of theproperties of the antibody as a labelling reagent.

Hereafter, a method for producing a monoclonal antibody will bedescribed in detail along with the above described steps. However, themethod of producing the aforementioned antibody is not limited thereto,and, for example, antibody-producing cells other than splenic cells andmyelomas can also be used.

(a) Purification of Antigen

As an antigen, GARP prepared by the above described method, or a portionthereof, can be used.

Alternatively, a membrane fraction prepared from GARP-expressingrecombinant somatic cells, or such GARP-expressing recombinant somaticcells themselves, or further, a partial peptide of the protein of thepresent invention, which is chemically synthesized according to a methodwell known to a person skilled in the art, can also be used as anantigen.

(b) Preparation of Antibody-Producing Cells

The antigen obtained in step (a) is mixed with an auxiliary agent, suchas a Freund complete or incomplete adjuvant, or potassium alum, toprepare an immunogen, and thereafter, an experimental animal isimmunized with the immunogen. As such an experimental animal, an animalused in known methods for producing hybridomas can be used without anyproblems. Specific examples of such an animal that can be used hereininclude a mouse, a rat, a goat, sheep, a bovine, and a horse. From theviewpoint of the availability of myeloma cells to be fused with theexcised antibody-producing cells, etc., a mouse or a rat is preferablyused as the animal to be immunized.

The strains of actually used mice and rats are not particularly limited.In the case of mice, examples of the strain that can be used hereininclude A, AKR, BALB/c, BDP, BA, CE, C3H, 57BL, C57BL, C57L, DBA, FL,HTH, HT1, LP, NZB, NZW, RF, R III, SJL, SWR, WB, and 129. On the otherhand, in the case of rats, examples of the strain that can be usedherein include Wistar, Low, Lewis, Sprague Dawley, ACI, BN, and Fischer.

These mice and rats are available from experimental animal breeders anddistributors, such as CLEA Japan, Inc. and CHARLES RIVER LABORATORIESJAPAN, INC.

Among others, taking into consideration fusion compatibility with themyeloma cells discussed below, the BALB/c strain in the case of mice,and the Wistar and Low strains in the case of rats, are particularlypreferable as animals to be immunized.

Moreover, taking into consideration the homology between the antigens ofhumans and mice, it is also preferable to use mice whose biologicalmechanism for removing autoantibodies has been reduced, namely,autoimmune disease mice.

The age of these mice or rats upon immunization is preferably 5 to 12weeks old, and more preferably 6 to 8 weeks old.

In order to immunize animals with GARP or a recombinant thereof, knownmethods, which are described in detail, for example, in Weir, D. M.,Handbook of Experimental Immunology, Vol. I. II. III., BlackwellScientific Publications, Oxford (1987), Kabat, E. A. and Mayer, M. M.,Experimental Immunochemistry, Charles C Thomas Publisher Springfield,Ill. (1964), etc. can be applied.

Among these immunization methods, a method preferably applied in thepresent invention is specifically the following method, for example.

That is to say, first, cells, in which a membrane protein fraction usedas an antigen, or an antigen has been expressed, are intradermally orintraperitoneally administered to an animal.

In order to enhance immunization efficiency, the combined use thereof ispreferable. If intradermal administration is carried out in a first halfof an administration regime, and intraperitoneal administration iscarried out in a latter half thereof or only in the final instance ofadministration, immunization efficiency can be particularly enhanced.

The administration schedule of the antigen is different depending on thetype of animal to be immunized, individual differences, etc. In general,3 to 6 antigen doses and a dosing interval of 2 to 6 weeks arepreferable, and 3 or 4 antigen doses and a dosing interval of 2 to 4weeks are more preferable.

The applied dose of an antigen is different depending on the type ofanimal to be immunized, individual differences, etc. It is generally0.05 to 5 mg, and preferably approximately 0.1 to 0.5 mg.

The booster is carried out 1 to 6 weeks, preferably 2 to 4 weeks, andmore preferably 2 to 3 weeks, after the above described administrationof the antigen.

The applied dose of the antigen, when the booster is carried out, isdifferent depending on the type of animal, the size thereof, etc. In thecase of a mouse for example, the applied dose of the antigen isgenerally 0.05 to 5 mg, preferably 0.1 to 0.5 mg, and more preferablyapproximately 0.1 to 0.2 mg.

1 to 10 days, preferably 2 to 5 days, and more preferably 2 or 3 daysafter completion of the above described booster, splenic cells orlymphocytes comprising antibody-producing cells are aseptically removedfrom the immunized animal. At that time, the antibody titer is measured.An animal, in which the antibody titer has been sufficiently increased,is used as a supply source of antibody-producing cells, so that theefficiency of the subsequent operations can be enhanced.

Examples of the method of measuring an antibody titer used herein caninclude a RIA method and an ELISA method, but are not limited thereto.

With regard to the measurement of an antibody titer in the presentinvention, the ELISA method can, for example, be carried out accordingto the following procedures.

First, a purified or a partially purified antigen is adsorbed on thesurface of a solid phase, such as a 96-well plate for ELISA, and anothersolid surface, on which such an antigen is not adsorbed, is covered witha protein irrelevant to the antigen, such as bovine serum albumin(hereinafter referred to as “BSA”). The surfaces are washed, and arethen allowed to come into contact with a serially diluted sample used asa primary antibody (e.g., mouse serum), so that an antibody in thesample is allowed to bind to the above described antigen.

Thereafter, an enzyme-labeled antibody against the mouse antibody isadded as a secondary antibody, so that it is allowed to bind to themouse antibody, followed by washing. After that, a substrate of theenzyme is added thereto, and a change in the absorbance due to colordevelopment based on the substrate decomposition, etc., is thenmeasured, so that the antibody titer is calculated.

Antibody-producing cells can be separated from the splenic cells orlymphocytes of the immunized animal according to known methods (e.g.,Kohler et al., Nature (1975) 256, p. 495; Kohler et al., Eur. J.Immunol. (1977) 6, p. 511; Milstein et al., Nature (1977), 266, p. 550;Walsh, Nature, (1977) 266, p. 495). For example, in the case of spleniccells, there can be adopted a common method which comprises mincing thespleen, then filtrating the cells through a stainless steel mesh, thensuspending the filtrate in Eagle's minimal essential medium (MEM) toseparate antibody-producing cells.

(c) Preparation of Myeloma Cells (Hereinafter Referred to as “Myelomas”)

Myeloma cells used in cell fusion are not particularly limited, and thecells can be selected from known cell lines, as appropriate, and canthen be used. Taking into consideration issues of convenience in theselection of hybridomas from fused cells, HGPRT (Hypoxanthine-GUANINEphosphoribosyl transferase)-deficient cell lines, the selectionprocedures of which have been established, is preferably used.

That is, examples of such HGPRT-deficient cell lines include:mouse-derived X63-Ag8 (X63), NS1-ANS/1 (NS1), P3X63-Ag8. U1 (P3U1),X63-Ag8.653 (X63.653), SP2/0-Agl4 (SP2/0), MPC11-45.6TG1.7 (45.6TG), FO,S149/5XXO, and BU. 1; rat-derived 210. RSY3. Ag. 1. 2.3 (Y3); andhuman-derived U266AR (SKO-007), GM1500-GTG-A12 (GM1500), UC729-6,LICR-LOW-HMy2 (HMy2), and 8226AR/NIP4-1 (NP41). These HGPRT-deficientcell lines are available from, for example, American Type CultureCollection (ATCC).

These cell lines are sub-cultured in a suitable medium, such as an8-azaguanine medium [a medium prepared by adding 8-azaguanine to anRPMI-1640 medium comprising glutamine, 2-mercaptoethanol, gentamicin,and fetal calf serum (hereinafter referred to as “FCS”)], Iscove'sModified Dulbecco's Medium (hereinafter referred to as “IMDM”), orDulbecco's Modified Eagle Medium (hereinafter referred to as “DMEM”).Three or four days before cell fusion, the cells are sub-cultured in anormal medium [e.g., ASF104 medium comprising 10% FCS (manufactured byAjinomoto Co., Inc.)] to ensure not less than 2×10⁷ cells on the day ofcell fusion.

(d) Cell Fusion

Antibody-producing cells can be fused with myeloma cells, asappropriate, according to known methods (Weir, D. M., Handbook ofExperimental Immunology, Vol. I. II. III., Blackwell ScientificPublications, Oxford (1987), Kabat, E. A. and Mayer, M. M., ExperimentalImmunochemistry, Charles C Thomas Publisher Springfield, Ill. (1964),etc.) under conditions in which the survival rate of cells is notexcessively reduced.

Examples of such a method that can be used herein include a chemicalmethod comprising mixing antibody-producing cells with myeloma cells ina high-concentration polymer solution such as polyethylene glycol, and aphysical method utilizing electric stimulation. Among these methods, aspecific example of the above described chemical method is as follows.

That is, when polyethylene glycol is used as a high-concentrationpolymer solution, antibody-producing cells are mixed with myeloma cellsin a polyethylene glycol solution with a molecular weight of 1500 to6000, preferably 2000 to 4000, at a temperature of 30° C. to 40° C.,preferably 35° C. to 38° C., and for 1 to 10 minutes, preferably for 5to 8 minutes.

(e) Selection of Hybridoma Group

The method of selecting hybridomas obtained by the above described cellfusion is not particularly limited. In general, a HAT(hypoxanthine-aminopterin-thymidine) selection method (Kohler et al.,Nature (1975) 256, p. 495; Milstein et al., Nature (1977) 266, p. 550)is applied.

This method is effective, when hybridomas are obtained using myelomacells of an HGPRT-deficient cell line that cannot survive inaminopterin.

Specifically, unfused cells and hybridomas are cultured in a HAT medium,so that only the hybridomas that are resistant to aminopterin areallowed to remain and grow selectively.

(f) Division into Single Cell Clones (Cloning)

As hybridoma cloning methods, known methods such as a methyl cellulosemethod, a soft agarose method, or a limiting dilution method can, forexample, be applied (see, for example, Barbara, B. M. and Stanley, M.S.: Selected Methods in Cellular Immunology, W. H. Freeman and Company,San Francisco (1980)). Among these methods, three-dimensional culturemethods, such as a methyl cellulose method, are particularly preferable.For example, a hybridoma group formed by cell fusion is suspended in amethyl cellulose medium such as ClonaCell-HY Selection Medium D(manufactured by StemCell Technologies, #03804), and is then cultured.Thereafter, the formed hybridoma colonies are harvested, so thatmonoclonal hybridomas can be obtained. The harvested hybridoma coloniesare each cultured, and the obtained hybridoma culture supernatant, inwhich a stable antibody titer is observed, is selected as a GARPmonoclonal antibody-producing hybridoma strain.

Examples of the thus established hybridoma strain can include GARPhybridomas 151D and 198D. In the present description, an antibodyproduced by GARP hybridomas 151D and 198D is referred to as a “151Dantibody” or “198D antibody,” or it is simply referred to as “151D” or“198D.”

The heavy chain variable region of the 151D antibody has the amino acidsequence shown in SEQ ID NO: 15 in the sequence listing. In addition,the light chain variable region of the 151D antibody has the amino acidsequence shown in SEQ ID NO: 17 in the sequence listing. It is to benoted that the amino acid sequence of the heavy chain variable regionshown in SEQ ID NO: 15 in the sequence listing is encoded by thenucleotide sequence shown in SEQ ID NO: 14 in the sequence listing. Itis also to be noted that the amino acid sequence of the light chainvariable region shown in SEQ ID NO: 17 in the sequence listing isencoded by the nucleotide sequence shown in SEQ ID NO: 16 in thesequence listing.

The heavy chain variable region of the 198D antibody has the amino acidsequence shown in SEQ ID NO: 19 in the sequence listing. In addition,the light chain variable region of the 198D antibody has the amino acidsequence shown in SEQ ID NO: 21 in the sequence listing. It is to benoted that the amino acid sequence of the heavy chain variable regionshown in SEQ ID NO: 19 in the sequence listing is encoded by thenucleotide sequence shown in SEQ ID NO: 18 in the sequence listing. Itis also to be noted that the amino acid sequence of the light chainvariable region shown in SEQ ID NO: 21 in the sequence listing isencoded by the nucleotide sequence shown in SEQ ID NO: 20 in thesequence listing.

(g) Preparation of Monoclonal Antibody by Culturing Hybridomas

The thus selected hybridomas are cultured, so that monoclonal antibodiescan be efficiently obtained. Before performing the culture, it isdesirable to screen for hybridomas that produce a monoclonal antibody ofinterest.

For this screening, known methods can be adopted.

The antibody titer can be measured in the present invention by, forexample, the ELISA method described in the above section (b).

The hybridomas obtained by the aforementioned methods can be preservedin liquid nitrogen or in a freezer at a temperature of −80° C. or lowerin the form of a frozen state.

After completion of the cloning, the hybridomas are cultured, whilereplacing the HT medium with a normal medium.

Mass culture is carried out by rotary culture or spinner culture, usinga large culture bottle. A supernatant obtained from this mass culture ispurified according to methods well known to a person skilled in the art,such as gel filtration, so as to obtain a monoclonal antibodyspecifically binding to the protein of the present invention.

Moreover, hybridomas are injected into the abdominal cavity of a mouseof the same strain (e.g., the above described BALB/c), or a Nu/Nu mouse,and the hybridomas are allowed to grow therein, so as to obtain ascitescomprising a large amount of the monoclonal antibody of the presentinvention.

When the hybridomas are administered into the abdominal cavity of such amouse, a larger amount of ascites can be obtained if mineral oil such as2,6,10,14-tetramethylpentadecane (pristane) has previously beenadministered to the mouse (3 to 7 days before administration of thehybridomas).

For instance, suppose that an immunosuppressive agent has previouslybeen administered into the abdominal cavity of a mouse of the samestrain as the hybridomas, so that T cells are deactivated. Twenty daysafter the injection, 10⁶ to 10⁷ hybridomas and/or clonal cells aresuspended in a medium comprising no serum (0.5 ml), and the suspensionis then administered into the abdominal cavity. When the normal abdomenhas swollen and ascites has gathered, the ascites is collected from themouse. According to this method, a monoclonal antibody in aconcentration that is about 100 times or more than in a culture solutioncan be obtained.

The monoclonal antibody obtained by the above described method can bepurified, for example, by the method described in Weir, D. M.: Handbookof Experimental Immunology, Vol. I, II, III, Blackwell ScientificPublications, Oxford (1978).

The thus obtained monoclonal antibody has high antigen specificity toGARP.

(h) Assay of Monoclonal Antibody

The isotype and subtype of the obtained monoclonal antibody can bedetermined as follows.

First, examples of the assay method can include an ouchterlony method,an ELISA method, and a RIA method.

The Ouchterlony method is simple, but when the concentration of amonoclonal antibody is low, a concentration procedure is necessary.

On the other hand, when the ELISA method or the RIA method is used, aculture supernatant is directly reacted with an antigen-adsorbed solidphase, and an antibody corresponding to various immunoglobulin isotypesor subclasses is used as a secondary antibody, so that the isotype andsubtype of the monoclonal antibody can be identified.

As a simpler method, a commercially available identification kit (e.g.,Mouse Typer Kit; manufactured by BioRad), etc. can also be utilized.

Moreover, quantification of a protein can be carried out by a FolinLowry method and a method of calculating the value from the absorbanceat 280 nm [1.4 (OD 280)=1 mg/ml immunoglobulin].

Furthermore, also in a case where the steps (a) to (h) in the above (2)are carried out again and a monoclonal antibody is independentlyobtained separately, an antibody having properties equivalent to thoseof an 105F antibody, an 110F antibody, a 151D-derived antibody(humanized 151D antibody) and a 198D-derived antibody (humanized 198Dantibody) can be obtained. An example of such an antibody can be anantibody binding to the same epitope, to which each of the abovedescribed antibodies binds. The 105F antibody recognizes the amino acidsequence portions at amino acid positions 366 to 377, 407 to 445, and456 to 470 in the amino acid sequence (SEQ ID NO: 1) of GARP, and bindsthereto; the 110F antibody recognizes the amino acid sequence portionsat amino acid positions 54 to 112 and 366 to 392 in the amino acidsequence (SEQ ID NO: 1) of GARP, and binds thereto; the 151D-derivedantibody (humanized 151D antibody) recognizes the amino acid sequence atamino acid positions 352 to 392 in the amino acid sequence (SEQ IDNO: 1) of GARP, and binds thereto; and the 198D-derived antibody(humanized 198D antibody) recognizes the amino acid sequence at aminoacid positions 18 to 112 in the amino acid sequence (SEQ ID NO: 1) ofGARP, and binds thereto. Accordingly, particular examples of theaforementioned epitope can include the aforementioned regions in theamino acid sequence of GARP.

If a newly prepared monoclonal antibody binds to a partial peptide or apartial three-dimensional structure to which the above described 105Fantibody, etc. binds, it can be determined that the monoclonal antibodybinds to the same epitope, to which the above described 105F antibody,etc. binds. Moreover, by confirming that the monoclonal antibodycompetes with the above described antibodies such as the 105F antibodyin the binding of the antibodies to GARP (i.e., the monoclonal antibodyinterferes with the binding of the above described antibodies such asthe 105F antibody to GARP), it can be determined that the monoclonalantibody binds to the same epitope, to which the above described 105Fantibody, etc. binds, even if the specific sequence or structure of theepitope has not been determined. When it is confirmed that themonoclonal antibody binds to the same epitope to which the 105Fantibody, etc. binds, then it is strongly expected that the monoclonalantibody should have properties equivalent to the above describedantibodies such as the 105F antibody.

(3) Other Antibodies

The antibody of the present invention also includes geneticallyrecombinant antibodies that have been artificially modified for thepurpose of reducing heterogenetic antigenicity to humans, such as achimeric antibody, a humanized antibody and the above described humanantibodies, as well as the above described monoclonal antibody againstGARP. These antibodies can be produced by known methods.

The obtained antibody can be purified to a homogenous state. Forseparation and purification of the antibody, separation and purificationmethods used for ordinary proteins may be used. For example, columnchromatography, filtration, ultrafiltration, salting-out, dialysis,preparative polyacrylamide gel electrophoresis, isoelectric focusing,etc. are appropriately selected and combined with one another, so thatthe antibody can be separated and purified (Strategies for ProteinPurification and Characterization: A Laboratory Course Manual, Daniel R.Marshak et al. eds., Cold Spring Harbor Laboratory Press (1996);Antibodies: A Laboratory Manual. Ed Harlow and David Lane, Cold SpringHarbor Laboratory (1988)), but examples of the separation andpurification methods are not limited thereto.

Examples of the chromatography can include affinity chromatography, ionexchange chromatography, hydrophobic chromatography, gel filtrationchromatography, reverse phase chromatography, and absorptionchromatography.

These chromatographic techniques can be carried out using liquidchromatography such as HPLC or FPLC.

Examples of the column used in the affinity chromatography can include aProtein A column and a Protein G column.

Examples of the column involving the use of Protein A can include HyperD, POROS, and Sepharose F. F. (Pharmacia).

Also, using an antigen-immobilized carrier, an antibody can be purifiedby utilizing the binding activity of the antibody to the antigen.

The obtained antibodies are evaluated, in terms of their bindingactivity to the antigen, according to the method described in theExamples discussed below, etc., so that a preferred antibody can beselected.

The stability of an antibody can be used as an indicator for comparisonof the properties of antibodies. A differential scanning calorimeter(DSC) is a device capable of promptly and exactly measuring a thermaldenaturation midpoint (Tm) that is a good indicator for the relativestructural stability of a protein. By using DSC to measure Tm values andmaking a comparison regarding the obtained values, differences in thethermal stability can be compared. It is known that the preservationstability of an antibody has a certain correlation with the thermalstability of the antibody (Lori Burton, et al., PharmaceuticalDevelopment and Technology (2007) 12, pp. 265-273), and thus, apreferred antibody can be selected using thermal stability as anindicator. Examples of other indicators for selection of an antibody caninclude high yield in suitable host cells and low agglutination in anaqueous solution. For example, since an antibody with the highest yielddoes not always exhibit the highest thermal stability, it is necessaryto select an antibody most suitable for administration to a human bycomprehensively determining it based on the aforementioned indicators.

An example of the anti-GARP human antibody of the present invention canbe an anti-GARP human antibody obtained by the above described phagedisplay method, and preferred examples of the present anti-GARP humanantibody can include a 105F antibody and a 110F antibody, each of whichhas the following structure.

The heavy chain of the 105F antibody has the amino acid sequence shownin SEQ ID NO: 2 in the sequence listing. In the heavy chain amino acidsequence shown in SEQ ID NO: 2 in the sequence listing, the amino acidsequence consisting of the amino acid residues at positions 1 to 118 isa variable region, whereas the amino acid sequence consisting of theamino acid residues at positions 119 to 448 is a constant region. In SEQID NO: 2 in the sequence listing, this variable region has CDRH1consisting of the amino acid sequence at amino acid positions 26 to 35,CDRH2 consisting of the amino acid sequence at amino acid positions 50to 66, and CDRH3 consisting of the amino acid sequence at amino acidpositions 99 to 107. In addition, the sequence of SEQ ID NO: 2 is shownin FIG. 2.

The light chain of the 105F antibody has the amino acid sequence shownin SEQ ID NO: 3 in the sequence listing. In the light chain amino acidsequence shown in SEQ ID NO: 3 in the sequence listing, the amino acidsequence consisting of the amino acid residues at positions 1 to 112 isa variable region, whereas the amino acid sequence consisting of theamino acid residues at positions 113 to 217 is a constant region. In SEQID NO: 3 in the sequence listing, this variable region has CDRL1consisting of the amino acid sequence at amino acid positions 23 to 36,CDRL2 consisting of the amino acid sequence at amino acid positions 52to 58, and CDRL3 consisting of the amino acid sequence at amino acidpositions 91 to 101. In addition, the sequence of SEQ ID NO: 3 is shownin FIG. 3.

The heavy chain of the 110F antibody has the amino acid sequence shownin SEQ ID NO: 4 in the sequence listing. In the heavy chain amino acidsequence shown in SEQ ID NO: 4 in the sequence listing, the amino acidsequence consisting of the amino acid residues at positions 1 to 123 isa variable region, whereas the amino acid sequence consisting of theamino acid residues at positions 124 to 453 is a constant region. In SEQID NO: 4 in the sequence listing, this variable region has CDRH1consisting of the amino acid sequence at amino acid positions 26 to 35,CDRH2 consisting of the amino acid sequence at amino acid positions 50to 66, and CDRH3 consisting of the amino acid sequence at amino acidpositions 99 to 112. In addition, the sequence of SEQ ID NO: 4 is shownin FIG. 4.

The light chain of the 110F antibody has the amino acid sequence shownin SEQ ID NO: 5 in the sequence listing. In the light chain amino acidsequence shown in SEQ ID NO: 5 in the sequence listing, the amino acidsequence consisting of the amino acid residues at positions 1 to 111 isa variable region, whereas the amino acid sequence consisting of theamino acid residues at positions 112 to 216 is a constant region. In SEQID NO: 5 in the sequence listing, this variable region has CDRL1consisting of the amino acid sequence at amino acid positions 23 to 36,CDRL2 consisting of the amino acid sequence at amino acid positions 52to 58, and CDRL3 consisting of the amino acid sequence at amino acidpositions 91 to 100. In addition, the sequence of SEQ ID NO: 5 is shownin FIG. 5.

The amino acid sequence of the 105F antibody heavy chain shown in SEQ IDNO: 2 in the sequence listing is encoded by the nucleotide sequenceshown in SEQ ID NO: 6 in the sequence listing. The nucleotide sequenceconsisting of the nucleotides at nucleotide positions 1 to 354 in thenucleotide sequence shown in SEQ ID NO: 6 in the sequence listingencodes the heavy chain variable region of the 105F antibody, and thenucleotide sequence consisting of the nucleotides at nucleotidepositions 355 to 1344 encodes the heavy chain constant region of the105F antibody. As shown in SEQ ID NO: 6, the nucleotide sequenceencoding the variable region has a polynucleotide consisting of thenucleotide sequence at nucleotide positions 76 to 105 encoding CDRH1, apolynucleotide consisting of the nucleotide sequence at nucleotidepositions 148 to 198 encoding CDRH2, and a polynucleotide consisting ofthe nucleotide sequence at nucleotide positions 295 to 321 encodingCDRH3. In addition, the sequence of SEQ ID NO: 6 is shown in FIG. 6.

The amino acid sequence of the 105F antibody light chain shown in SEQ IDNO: 3 in the sequence listing is encoded by the nucleotide sequenceshown in SEQ ID NO: 7 in the sequence listing. The nucleotide sequenceconsisting of the nucleotides at nucleotide positions 1 to 336 in thenucleotide sequence shown in SEQ ID NO: 7 in the sequence listingencodes the light chain variable region of the 105F antibody, and thenucleotide sequence consisting of the nucleotides at nucleotidepositions 337 to 651 encodes the light chain constant region of the 105Fantibody. As shown in SEQ ID NO: 7, the nucleotide sequence encoding thevariable region has a polynucleotide consisting of the nucleotidesequence at nucleotide positions 67 to 108 encoding CDRL1, apolynucleotide consisting of the nucleotide sequence at nucleotidepositions 154 to 174 encoding CDRL2, and a polynucleotide consisting ofthe nucleotide sequence at nucleotide positions 271 to 303 encodingCDRL3. In addition, the sequence of SEQ ID NO: 7 is shown in FIG. 7.

The amino acid sequence of the 110F antibody heavy chain shown in SEQ IDNO: 4 in the sequence listing is encoded by the nucleotide sequenceshown in SEQ ID NO: 8 in the sequence listing. The nucleotide sequenceconsisting of the nucleotides at nucleotide positions 1 to 369 in thenucleotide sequence shown in SEQ ID NO: 8 in the sequence listingencodes the heavy chain variable region of the 110F antibody, and thenucleotide sequence consisting of the nucleotides at nucleotidepositions 370 to 1359 encodes the heavy chain constant region of the110F antibody. As shown in SEQ ID NO: 8, the nucleotide sequenceencoding the variable region has a polynucleotide consisting of thenucleotide sequence at nucleotide positions 76 to 105 encoding CDRH1, apolynucleotide consisting of the nucleotide sequence at nucleotidepositions 148 to 198 encoding CDRH2, and a polynucleotide consisting ofthe nucleotide sequence at nucleotide positions 295 to 336 encodingCDRH3. In addition, the sequence of SEQ ID NO: 8 is shown in FIG. 8.

The amino acid sequence of the 110F antibody light chain shown in SEQ IDNO: 5 in the sequence listing is encoded by the nucleotide sequenceshown in SEQ ID NO: 9 in the sequence listing. The nucleotide sequenceconsisting of the nucleotides at nucleotide positions 1 to 333 in thenucleotide sequence shown in SEQ ID NO: 9 in the sequence listingencodes the light chain variable region of the 110F antibody, and thenucleotide sequence consisting of the nucleotides at nucleotidepositions 334 to 648 encodes the light chain constant region of the 110Fantibody. As shown in SEQ ID NO: 9, the nucleotide sequence encoding thevariable region has a polynucleotide consisting of the nucleotidesequence at nucleotide positions 67 to 108 encoding CDRL1, apolynucleotide consisting of the nucleotide sequence at nucleotidepositions 154 to 174 encoding CDRL2, and a polynucleotide consisting ofthe nucleotide sequence at nucleotide positions 271 to 300 encodingCDRL3. In addition, the sequence of SEQ ID NO: 9 is shown in FIG. 9.

With regard to the antibody of the present invention, in addition to theabove described anti-GARP human antibody, even in a case where anantibody is independently obtained, separately, according to a methodother than the above described method of obtaining an antibody,antibodies having cytotoxicity equivalent to that of the 105F antibodyor the 110F antibody can be obtained. An example of such an antibody canbe an antibody binding to the same epitope to which the 105F antibody orthe 110F antibody binds.

If a newly produced human antibody binds to a partial peptide or apartial three-dimensional structure, to which the 105F antibody or the110F antibody binds, it can be determined that the produced antibodybinds to the same epitope, to which the 105F antibody or the 110Fantibody binds. In addition, by confirming that the concerned antibodycompetes with the 105F antibody or the 110F antibody for the bindingthereof to GARP (i.e., the concerned antibody interferes with thebinding of the 105F antibody or the 110F antibody to GARP), it can bedetermined that the concerned antibody binds to the same epitope, towhich the 105F antibody or the 110F antibody binds, even if the specificsequence or structure of the epitope has not been determined. If it isconfirmed that the concerned antibody binds to the same epitope to whichthe 105F antibody or the 110F antibody binds, then it is stronglyexpected that the concerned antibody should have cytotoxicity equivalentto that of the 105F antibody or the 110F antibody.

Moreover, the antibody of the present invention includes artificiallymodified, genetically recombinant antibodies. These antibodies can beproduced using known methods. The antibody concerned is preferably anantibody having, at least, the same 6 CDRs as the heavy chain and lightchain of the above described 105F antibody or 110F antibody, and alsohaving ADCC activity and inhibitory activity on the immunosuppressivefunction of Treg. The concerned antibody is not limited to a specificantibody, as long as it has the aforementioned properties. The antibodyis more preferably an antibody having the heavy chain variable regionand light chain variable region of the above described 105F antibody or110F antibody.

Furthermore, by combining sequences showing a high homology to the heavychain amino acid sequence and light chain amino acid sequence of the105F antibody or the 110F antibody with each other, it is possible toselect an antibody having an activity equivalent to the above describedantibody. Such a homology is a homology of generally 80% or more,preferably 90% or more, more preferably 95% or more, and most preferably99% or more (however, each CDR is identical to that of each of the abovedescribed antibodies). Further, it is also possible to select anantibody having an activity equivalent to each of the above describedantibodies by incorporating an amino acid sequence comprising asubstitution, deletion or addition of one or several amino acid residuesto the amino acid sequence of the above described heavy chain or lightchain (excluding each CDR site).

Still further, examples of the anti-GARP antibody according to thepresent invention can include the following chimeric antibodies andhumanized antibodies.

Example of a chimeric antibody can include antibodies in which avariable region and a constant region are heterologous to each other,such as a chimeric antibody formed by conjugating the variable region ofa mouse- or rat-derived antibody to a human-derived constant region (seeProc. Natl. Acad. Sci. U.S.A., 81, 6851-6855, (1984)).

A chimeric antibody derived from rat anti-human GARP antibody 151D is anantibody consisting of a heavy chain comprising a heavy chain variableregion consisting of the amino acid sequence consisting of the aminoacid residues at positions 1 to 117 shown in SEQ ID NO: 15, and a lightchain comprising a light chain variable region consisting of the aminoacid sequence consisting of the amino acid residues at positions 1 to109 shown in SEQ ID NO: 17, and this chimeric antibody may have aconstant region derived from any given human.

Moreover, a chimeric antibody derived from a rat anti-human GARPantibody 198D is an antibody consisting of a heavy chain comprising aheavy chain variable region consisting of the amino acid sequenceconsisting of the amino acid residues at positions 1 to 120 shown in SEQID NO: 19, and a light chain comprising a light chain variable regionconsisting of the amino acid sequence consisting of the amino acidresidues at positions 1 to 109 shown in SEQ ID NO: 21, and this chimericantibody may have a constant region derived from any given human.

Examples of such a chimeric antibody can include: an antibody consistingof a heavy chain having the amino acid sequence consisting of the aminoacid residues at positions 20 to 466 shown in SEQ ID NO: 25 in thesequence listing, and a light chain having the amino acid sequenceconsisting of the amino acid residues at positions 21 to 234 shown inSEQ ID NO: 27 therein; and an antibody consisting of a heavy chainhaving the amino acid sequence consisting of the amino acid residues atpositions 20 to 469 shown in SEQ ID NO: 29 in the sequence listing, anda light chain having the amino acid sequence consisting of the aminoacid residues at positions 21 to 234 shown in SEQ ID NO: 31 therein.

It is to be noted that, in the heavy chain sequence shown in SEQ ID NO:25 in the sequence listing, the amino acid sequence consisting of theamino acid residues at positions 1 to 19 is a signal sequence, the aminoacid sequence consisting of the amino acid residues at positions 20 to136 is a variable region, and the amino acid sequence consisting of theamino acid residues at positions 137 to 466 is a constant region.

It is also to be noted that, in the light chain sequence shown in SEQ IDNO: 27 in the sequence listing, the amino acid sequence consisting ofthe amino acid residues at positions 1 to 20 is a signal sequence, theamino acid sequence consisting of the amino acid residues at positions21 to 129 is a variable region, and the amino acid sequence consistingof the amino acid residues at positions 130 to 234 is a constant region.

It is further to be noted that, in the heavy chain sequence shown in SEQID NO: 29 in the sequence listing, the amino acid sequence consisting ofthe amino acid residues at positions 1 to 19 is a signal sequence, theamino acid sequence consisting of the amino acid residues at positions20 to 139 is a variable region, and the amino acid sequence consistingof the amino acid residues at positions 140 to 469 is a constant region.

It is further to be noted that, in the light chain sequence shown in SEQID NO: 31 in the sequence listing, the amino acid sequence consisting ofthe amino acid residues at positions 1 to 20 is a signal sequence, theamino acid sequence consisting of the amino acid residues at positions21 to 129 is a variable region, and the amino acid sequence consistingof the amino acid residues at positions 130 to 234 is a constant region.

The amino acid sequence of the heavy chain of the c151D antibody shownin SEQ ID NO: 25 in the sequence listing is encoded by the nucleotidesequence shown in SEQ ID NO: 24 in the sequence listing. The nucleotidesequence consisting of the nucleotides at nucleotide positions 1 to 57in the nucleotide sequence shown in SEQ ID NO: 24 in the sequencelisting encodes the heavy chain signal sequence of the c151D antibody,the nucleotide sequence consisting of the nucleotides at nucleotidepositions 58 to 408 therein encodes the heavy chain variable region ofthe c151D antibody, and the nucleotide sequence consisting of thenucleotides at nucleotide positions 409 to 1398 therein encodes theheavy chain constant region of the c151D antibody.

Moreover, the amino acid sequence of the light chain of the c151Dantibody shown in SEQ ID NO: 27 in the sequence listing is encoded bythe nucleotide sequence shown in SEQ ID NO: 26 in the sequence listing.The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 60 in the nucleotide sequence shown in SEQ ID NO: 26 inthe sequence listing encodes the light chain signal sequence of thec151D antibody, the nucleotide sequence consisting of the nucleotides atnucleotide positions 61 to 387 therein encodes the light chain variableregion of the c151D antibody, and the nucleotide sequence consisting ofthe nucleotides at nucleotide positions 388 to 702 therein encodes thelight chain constant region of the c151D antibody.

Furthermore, the amino acid sequence of the heavy chain of the c198Dantibody shown in SEQ ID NO: 29 in the sequence listing is encoded bythe nucleotide sequence shown in SEQ ID NO: 28 in the sequence listing.The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 57 in the nucleotide sequence shown in SEQ ID NO: 28 inthe sequence listing encodes the heavy chain signal sequence of thec198D antibody, the nucleotide sequence consisting of the nucleotides atnucleotide positions 58 to 417 therein encodes the heavy chain variableregion of the c198D antibody, and the nucleotide sequence consisting ofthe nucleotides at nucleotide positions 418 to 1407 therein encodes theheavy chain constant region of the c198D antibody.

Further, the amino acid sequence of the light chain of the c198Dantibody shown in SEQ ID NO: 31 in the sequence listing is encoded bythe nucleotide sequence shown in SEQ ID NO: 30 in the sequence listing.The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 60 in the nucleotide sequence shown in SEQ ID NO: 30 inthe sequence listing encodes the light chain signal sequence of thec198D antibody, the nucleotide sequence consisting of the nucleotides atnucleotide positions 61 to 387 therein encodes the light chain variableregion of the c198D antibody, and the nucleotide sequence consisting ofthe nucleotides at nucleotide positions 388 to 702 therein encodes thelight chain constant region of the c198D antibody.

Examples of the humanized antibody include a humanized antibody formedby incorporating only a complementarity determining region (CDR) into ahuman-derived antibody (see Nature (1986) 321, p. 522-525), and ahumanized antibody formed by transplanting the amino acid residues insome frameworks, as well as CDR sequences, into a human antibodyaccording to a CDR grafting method (International Publication No.WO90/07861).

However, a humanized antibody derived from the 151D antibody is notlimited to a specific humanized antibody, as long as it retains all 6CDR sequences of the 151D antibody and has an antitumor activity.

It is to be noted that the heavy chain variable region of the 151Dantibody has CDRH1 (GFTFSNYYMA) consisting of the amino acid sequenceconsisting of the amino acid residues at positions 26 to 35 in SEQ IDNO: 15 in the sequence listing, CDRH2 (SIGTVGGNTY) consisting of theamino acid sequence consisting of the amino acid residues at positions50 to 59 in SEQ ID NO: 15 therein, and CDRH3 (EDYGGFPH) consisting ofthe amino acid sequence consisting of the amino acid residues atpositions 99 to 106 in SEQ ID NO: 15 therein.

In addition, the light chain variable region of the 151D antibody hasCDRL1 (KASQNVGTNVD) consisting of the amino acid sequence consisting ofthe amino acid residues at positions 24 to 34 in SEQ ID NO: 17 in thesequence listing, CDRL2 (GASNRYT) consisting of the amino acid sequenceconsisting of the amino acid residues at positions 50 to 56 in SEQ IDNO: 17 therein, and CDRL3 (LQYKYNPYT) consisting of the amino acidsequence consisting of the amino acid residues at positions 89 to 97 inSEQ ID NO: 17 therein.

Moreover, the heavy chain variable region of the 198D antibody has CDRH1(GFSLTSFHVS) consisting of the amino acid sequence consisting of theamino acid residues at positions 26 to 35 in SEQ ID NO: 19 in thesequence listing, CDRH2 (TISSGGGTY) consisting of the amino acidsequence consisting of the amino acid residues at positions 50 to 58 inSEQ ID NO: 19 therein, and CDRH3 (ISGWGHYYVMDV) consisting of the aminoacid sequence consisting of the amino acid residues at positions 98 to109 in SEQ ID NO: 19 therein.

Furthermore, the light chain variable region of the 198D antibody hasCDRL1 (QASEDIYSGLA) consisting of the amino acid sequence consisting ofthe amino acid residues at positions 24 to 34 in SEQ ID NO: 21 in thesequence listing, CDRL2 (GAGSLQD) consisting of the amino acid sequenceconsisting of the amino acid residues at positions 50 to 56 in SEQ IDNO: 21 therein, and CDRL3 (QQGLKFPLT) consisting of the amino acidsequence consisting of the amino acid residues at positions 89 to 97 inSEQ ID NO: 21 therein.

A concrete example of a humanized antibody of the rat antibody 151D canbe any given combination of: a heavy chain comprising a heavy chainvariable region consisting of any one of (1) an amino acid sequenceconsisting of the amino acid residues at positions 20 to 136 shown inSEQ ID NO: 33 (h151D-H1) or 35 (h151D-H4) in the sequence listing, (2)an amino acid sequence having a homology of at least 95% or more to thesequence of a framework region other than at each CDR sequence in thesequence of the above (1), and (3) an amino acid sequence comprising adeletion, substitution or addition of one or several amino acids in thesequence of a framework region other than at each CDR sequence in thesequence of the above (1); and a light chain comprising a light chainvariable region consisting of any one of (4) an amino acid sequenceconsisting of the amino acid residues at positions 21 to 129 shown inSEQ ID NO: 37 (h151D-L1) or 39 (h151D-L4), (5) an amino acid sequencehaving a homology of at least 95% or more to the sequence of a frameworkregion other than at each CDR sequence in the sequence of the above (4),and (6) an amino acid sequence comprising a deletion, substitution oraddition of one or several amino acids in the sequence of a frameworkregion other than at each CDR sequence in the sequence of the above (4).

On the other hand, a concrete example of a humanized antibody of the ratantibody 198D can be any given combination of: a heavy chain comprisinga heavy chain variable region consisting of any one of (1) an amino acidsequence consisting of the amino acid residues at positions 20 to 139shown in SEQ ID NO: 41 (h198D-H3) in the sequence listing, (2) an aminoacid sequence having a homology of at least 95% or more to the sequenceof a framework region other than at each CDR sequence in the sequence ofthe above (1), and (3) an amino acid sequence comprising a deletion,substitution or addition of one or several amino acids in the sequenceof a framework region other than at each CDR sequence in the sequence ofthe above (1); and a light chain comprising a light chain variableregion consisting of any one of (4) an amino acid sequence consisting ofthe amino acid residues at positions 21 to 129 shown in SEQ ID NO: 43(h198D-L4) in the sequence listing, (5) an amino acid sequence having ahomology of at least 95% or more to the sequence of a framework regionother than at each CDR sequence in the sequence of the above (4), and(6) an amino acid sequence comprising a deletion, substitution oraddition of one or several amino acids in the sequence of a frameworkregion other than at each CDR sequence in the sequence of the above (4).

Examples of a preferred combination of a heavy chain and a light chainof the humanized 151D antibody can include: an antibody consisting of aheavy chain having a heavy chain variable region consisting of the aminoacid sequence consisting of the amino acid residues at positions 20 to136 shown in SEQ ID NO: 33, and a light chain having a light chainvariable region consisting of the amino acid sequence consisting of theamino acid residues at positions 21 to 129 shown in SEQ ID NO: 37; andan antibody consisting of a heavy chain having a heavy chain variableregion consisting of the amino acid sequence consisting of the aminoacid residues at positions 20 to 136 shown in SEQ ID NO: 35, and a lightchain having a light chain variable region consisting of the amino acidsequence consisting of the amino acid residues at positions 21 to 129shown in SEQ ID NO: 39.

Examples of a more preferred combination thereof can include: anantibody (h151D-H1L1) consisting of a heavy chain having the amino acidsequence shown in SEQ ID NO: 33 and a light chain having the amino acidsequence shown in SEQ ID NO: 37; and an antibody (h151D-H4L4) consistingof a heavy chain having the amino acid sequence shown in SEQ ID NO: 35and a light chain having the amino acid sequence shown in SEQ ID NO: 39.

An example of a preferred combination of the heavy chain and light chainof the humanized 198D antibody can be an antibody consisting of a heavychain having a heavy chain variable region consisting of the amino acidsequence consisting of the amino acid residues at positions 20 to 139shown in SEQ ID NO: 41, and a light chain having a light chain variableregion consisting of the amino acid sequence consisting of the aminoacid residues at positions 21 to 129 shown in SEQ ID NO: 43.

An example of a more preferred combination thereof can be an antibody(h198D-H3L4) consisting of a heavy chain having the amino acid sequenceshown in SEQ ID NO: 41 and a light chain having the amino acid sequenceshown in SEQ ID NO: 43.

By combining together sequences showing a high homology to the abovedescribed heavy chain amino acid sequences and light chain amino acidsequences, it is possible to select an antibody having cytotoxicityequivalent to each of the above described antibodies. Such a homology isa homology of generally 80% or more, preferably 90% or more, morepreferably 95% or more, and most preferably 99% or more. Moreover, alsoby combining with one another, amino acid sequences comprising asubstitution, deletion or addition of one or several amino acid residueswith respect to the amino acid sequence of a heavy chain or a lightchain, it is possible to select an antibody having cytotoxicityequivalent to each of the above described antibodies.

It is to be noted that the term “several” is used in the presentdescription to mean 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1to 4, 1 to 3, or 1 or 2.

The amino acid substitution in the present description is preferably aconservative amino acid substitution. The conservative amino acidsubstitution is a substitution occurring within an amino acid groupassociated with certain amino acid side chains. Preferred amino acidgroups are the following: acidic group=aspartic acid and glutamic acid;basic group=lysine, arginine, and histidine; non-polar group=alanine,valine, leucine, isoleucine, proline, phenylalanine, methionine, andtryptophan; and uncharged polar group=glycine, asparagine, glutamine,cysteine, serine, threonine, and tyrosine. Other preferred amino acidgroups are the following: aliphatic hydroxy group=serine and threonine;amide-containing group=asparagine and glutamine; aliphaticgroup=alanine, valine, leucine and isoleucine; and aromaticgroup=phenylalanine, tryptophan and tyrosine. Such amino acidsubstitution is preferably carried out to the extent that the propertiesof a substance having the original amino acid sequence are not impaired.

Homology between two types of amino acid sequences can be determinedusing default parameters of Blast algorithm version 2.2.2 (Altschul,Stephen F., Thomas L. Madden, Alejandro A. Schaffer, Jinghui Zhang,Zheng Zhang, Webb Miller, and David J. Lipman (1997), “Gapped BLAST andPSI-BLAST: a new generation of protein database search programs,”Nucleic Acids Res. 25: 3389-3402). The Blast algorithm can also be usedby accessing www.ncbi.nlm.nih.gov/blast through the internet. It is tobe noted that homology between the nucleotide sequence of the antibodyof the present invention and the nucleotide sequence of another antibodycan also be determined using the Blast algorithm.

In the amino acid sequence of the heavy chain of the humanized 151Dantibody shown in SEQ ID NO: 33 or 35 in the sequence listing, the aminoacid sequence consisting of the amino acid residues at positions 1 to 19is a signal sequence, the amino acid sequence consisting of the aminoacid residues at positions 20 to 136 is a variable region, and the aminoacid sequence consisting of the amino acid residues at positions 137 to466 is a constant region.

Moreover, in the amino acid sequence of the light chain of the humanized151D antibody shown in SEQ ID NO: 37 or 39 in the sequence listing, theamino acid sequence consisting of the amino acid residues at positions 1to 20 is a signal sequence, the amino acid sequence consisting of theamino acid residues at positions 21 to 129 is a variable region, and theamino acid sequence consisting of the amino acid residues at positions130 to 234 is a constant region.

Furthermore, in the amino acid sequence of the heavy chain of thehumanized 198D antibody shown in SEQ ID NO: 41 in the sequence listing,the amino acid sequence consisting of the amino acid residues atpositions 1 to 19 is a signal sequence, the amino acid sequenceconsisting of the amino acid residues at positions 20 to 139 is avariable region, and the amino acid sequence consisting of the aminoacid residues at positions 140 to 469 is a constant region.

Further, in the amino acid sequence of the light chain of the humanized198D antibody shown in SEQ ID NO: 43 in the sequence listing, the aminoacid sequence consisting of the amino acid residues at positions 1 to 20is a signal sequence, the amino acid sequence consisting of the aminoacid residues at positions 21 to 129 is a variable region, and the aminoacid sequence consisting of the amino acid residues at positions 130 to234 is a constant region.

The amino acid sequence of the heavy chain of the humanized 151Dantibody shown in SEQ ID NO: 33 or 35 in the sequence listing is encodedby the nucleotide sequence shown in SEQ ID NO: 32 or 34 in the sequencelisting, respectively. In addition, the sequence of SEQ ID NO: 33 isshown in FIG. 21, the sequence of SEQ ID NO: 35 is shown in FIG. 23, thesequence of SEQ ID NO: 32 is shown in FIG. 31, and the sequence of SEQID NO: 34 is shown in FIG. 33, respectively.

The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 57 in each nucleotide sequence encodes the heavy chainsignal sequence of the humanized 151D antibody, the nucleotide sequenceconsisting of the nucleotides at nucleotide positions 58 to 408 thereinencodes the heavy chain variable region of the humanized 151D antibody,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 409 to 1398 therein encodes the heavy chain constant region ofthe humanized 151D antibody

The amino acid sequence of the heavy chain of the humanized 198Dantibody shown in SEQ ID NO: 41 in the sequence listing is encoded bythe nucleotide sequence shown in SEQ ID NO: 40 in the sequence listing.In addition, the sequence of SEQ ID NO: 41 is shown in FIG. 25, and thesequence of SEQ ID NO: 40 is shown in FIG. 35.

The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 57 in the aforementioned nucleotide sequence encodes theheavy chain signal sequence of the humanized 198D antibody, thenucleotide sequence consisting of the nucleotides at nucleotidepositions 58 to 417 therein encodes the heavy chain variable region ofthe humanized 198D antibody, and the nucleotide sequence consisting ofthe nucleotides at nucleotide positions 418 to 1407 therein encodes theheavy chain constant region of the humanized 198D antibody.

The amino acid sequence of the light chain of the humanized 151Dantibody shown in SEQ ID NO: 37 or 39 in the sequence listing is encodedby the nucleotide sequence shown in SEQ ID NO: 36 or 38 in the sequencelisting, respectively. In addition, the sequence of SEQ ID NO: 37 isshown in FIG. 22, the sequence of SEQ ID NO: 39 is shown in FIG. 24, thesequence of SEQ ID NO: 36 is shown in FIG. 32, and the sequence of SEQID NO: 38 is shown in FIG. 34, respectively.

The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 60 in each nucleotide sequence encodes the light chainsignal sequence of the humanized 151D antibody, the nucleotide sequenceconsisting of the nucleotides at nucleotide positions 61 to 387 thereinencodes the light chain variable region of the humanized 151D antibody,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 388 to 702 therein encodes the light chain constant region ofthe humanized 151D antibody.

The amino acid sequence of the light chain of the humanized 198Dantibody shown in SEQ ID NO: 43 in the sequence listing is encoded bythe nucleotide sequence shown in SEQ ID NO: 42 in the sequence listing.In addition, the sequence of SEQ ID NO: 43 is shown in FIG. 26, and thesequence of SEQ ID NO: 42 is shown in FIG. 36.

The nucleotide sequence consisting of the nucleotides at nucleotidepositions 1 to 60 in the aforementioned nucleotide sequence encodes thelight chain signal sequence of the humanized 198D antibody, thenucleotide sequence consisting of the nucleotides at nucleotidepositions 61 to 387 therein encodes the light chain variable region ofthe humanized 198D antibody, and the nucleotide sequence consisting ofthe nucleotides at nucleotide positions 388 to 702 therein encodes thelight chain constant region of the humanized 198D antibody.

Homology between these nucleotide sequences and the nucleotide sequencesof other antibodies can also be determined using the Blast algorithm.

A further example of the antibody of the present invention can be ahuman antibody binding to the same epitope, to which the humanized 151Dantibody or the humanized 198D antibody also binds. An anti-GARP humanantibody means a human antibody having only the gene sequence of a humanchromosome-derived antibody. The anti-GARP human antibody can beobtained by the aforementioned method.

If a newly produced human antibody binds to a partial peptide or apartial three-dimensional structure, to which the humanized 151Dantibody or the humanized 198D antibody binds, it can be determined thatthe human antibody binds to the same epitope, to which the humanized151D antibody or the humanized 198D antibody binds. In addition, byconfirming that the human antibody competes with the humanized 151Dantibody or the humanized 198D antibody for the binding thereof to GARP(i.e., the human antibody interferes with the binding of the humanized151D antibody or the humanized 198D antibody to GARP), it can bedetermined that the human antibody binds to the same epitope, to whichthe humanized 151D antibody or humanized 198D antibody binds, even ifthe specific sequence or structure of the epitope has not beendetermined. If it is confirmed that the concerned human antibody bindsto the same epitope to which the humanized 151D antibody or thehumanized 198D antibody binds, then, it is strongly expected that thehuman antibody should have cytotoxicity equivalent to that of thehumanized 151D antibody or the humanized 198D antibody.

The chimeric antibody, humanized antibody, or human antibody obtained bythe aforementioned methods is evaluated by the methods described laterin the Examples, etc., in terms of binding activity to an antigen, andthus, a preferred antibody can be selected.

The present invention also includes a modification of an antibody. Theterm “modification” is used herein to mean the antibody of the presentinvention, which is chemically or biologically modified. Examples ofsuch a chemical modification include the binding of a chemical moiety toan amino acid skeleton, and the chemical modification of an N-linked orO-linked carbohydrate chain. Examples of such a biological modificationinclude antibodies which have undergone a posttranslational modification(e.g., an N-linked or O-linked sugar chain modification, N-terminal orC-terminal processing, deamidation, isomerization of aspartic acid, andoxidation of methionine), and antibodies, to the N-terminus of which amethionine residue is added as a result of having been allowed to beexpressed using prokaryote host cells. In addition, such a modificationalso includes labeled antibodies for enabling detection or isolation ofthe antibody of the present invention or an antigen, such as, forexample, an enzyme labeled antibody, a fluorescent-labeled antibody, andan affinity-labeled antibody. Such a modification of the antibody of thepresent invention is useful for the improvement of the stability andretention in blood of the original antibody of the present invention, areduction in antigenicity, detection or isolation of such an antibody orantigen, etc.

Moreover, by regulating a sugar chain modification (glycosylation,de-fucosylation, etc.) that binds to the antibody of the presentinvention, antibody-dependent cellular cytotoxicity can be enhanced. Astechniques of regulating the sugar chain modification of an antibody,those described in WO99/54342, WO2000/61739, WO2002/31140, etc. areknown, but the techniques are not limited thereto. The antibody of thepresent invention also includes antibodies in which the aforementionedsugar chain modification has been regulated.

After an antibody gene has been isolated, the gene is introduced into asuitable host to produce an antibody, using a suitable combination of ahost and an expression vector. A specific example of the antibody genecan be a combination of a gene encoding the heavy chain sequence of theantibody described in the present description and a gene encoding thelight chain sequence of the antibody described therein. Upontransformation of host cells, a heavy chain sequence gene and a lightchain sequence gene can be inserted into a single expression vector, orthese genes can instead each be inserted into different expressionvectors.

When eukaryotic cells are used as hosts, animal cells, plant cells oreukaryotic microorganisms can be used. Examples of animal cells includemammalian cells such as COS cells which are monkey cells (Gluzman, Y.,Cell (1981) 23, p. 175-182, ATCC CRL-1650), mouse fibroblasts NIH3T3(ATCC No. CRL-1658), and a dihydrofolate reductase-deficient cell lineof Chinese hamster ovary cells (CHO cells, ATCC CCL-61) (Urlaub, G. andChasin, L. A. Proc. Natl. Acad. Sci. U.S.A. (1980) 77, p. 4126-4220).

When prokaryotic cells are used as hosts, Escherichia coli or Bacillussubtilis can be used, for example.

An antibody gene of interest is introduced into these cells fortransformation, and the transformed cells are then cultured in vitro toobtain an antibody. In the aforementioned culture, there are cases whereyield is different depending on the sequence of the antibody, and thus,it is possible to select an antibody, which is easily produced as amedicament, from antibodies having equivalent binding activity, usingthe yield as an indicator. Accordingly, the antibody of the presentinvention also includes an antibody obtained by the above describedmethod for producing an antibody, which is characterized in that itcomprises a step of culturing the transformed host cells and a step ofcollecting an antibody of interest from the culture obtained in theaforementioned step.

It is known that the lysine residue at the carboxyl terminus of theheavy chain of an antibody produced in cultured mammalian cells isdeleted (Journal of Chromatography A, 705: 129-134 (1995)), and also, itis known that the two amino acid residues at the heavy chain carboxylterminus, glycine and lysine, are deleted, and that the proline residuepositioned at the carboxyl terminus is newly amidated (AnalyticalBiochemistry, 360: 75-83 (2007)). However, such deletion andmodification of these heavy chain sequences do not have an influence onthe antigen-binding activity and effector function (activation ofcomplement, antibody-dependent cellular cytotoxicity, etc.) of anantibody. Accordingly, the present invention also includes an antibodythat has undergone the aforementioned modification, and specificexamples of such an antibody include a deletion mutant comprising adeletion of 1 or 2 amino acids at the heavy chain carboxyl terminus, anda deletion mutant formed by amidating the aforementioned deletion mutant(e.g., a heavy chain in which the proline residue at the carboxylterminal site is amidated). However, deletion mutants involving adeletion at the carboxyl terminus of the heavy chain of the antibodyaccording to the present invention are not limited to the abovedescribed deletion mutants, as long as they retain antigen-bindingactivity and effector function. Two heavy chains constituting theantibody according to the present invention may be any one type of heavychain selected from the group consisting of a full length antibody andthe above described deletion mutants, or a combination of any two typesselected from the aforementioned group. The ratio of individual deletionmutants can be influenced by the types of cultured mammalian cells thatproduce the antibody according to the present invention, and the cultureconditions. The main ingredient of the antibody according to the presentinvention can be antibodies where one amino acid residue is deleted ateach of the carboxyl termini of the two heavy chains.

Examples of the isotype of the antibody of the present invention caninclude IgG (IgG1, IgG2, IgG3, and IgG4). Among others, IgG1 and IgG2are preferable.

Examples of the general function of an antibody can includeantigen-binding activity, activity of neutralizing the activity of anantigen, activity of enhancing the activity of an antigen, ADCCactivity, antibody dependent cellular phagocytosis (ADCP) activity, andcomplement-dependent cytotoxic (CDC) activity. The function of theantibody according to the present invention is binding activity to GARP,preferably ADCC activity, and more preferably cytotoxicity (antitumoractivity) caused by ADCC-mediated inhibition of Treg function. Moreover,the antibody of the present invention may have ADCP activity and/or CDCactivity, as well as ADCC activity. In particular, with regard tomedicaments comprising existing antitumor antibodies, it has beenreported that the medicaments directly act on tumor cells to blockgrowth signals, that they directly act on tumor cells to induce celldeath signals, that they suppress angiogenesis, that they cause ADCCactivity via NK cells, and that they induce CDC activity via complementto suppress the growth of tumor cells (J Clin Oncol 28: 4390-4399.(2010), Clin Cancer Res; 16 (1); 11-20. (2010)). However, with regard tothe ADCP activity of the anti-GARP antibody according to the inventionof the present application, at least, the present inventors have notknown that the ADCP activity had been reported as an activity of amedicament comprising an existing anti-GARP antitumor antibody.

The antibody of the present invention may be an antibody that has beenmultimerized to enhance affinity for an antigen. The antibody to bemultimerized may be either a single type of antibody, or multipleantibodies recognizing multiple epitopes of a single antigen. Examplesof a method of multimerizing an antibody can include the binding of anIgG CH3 domain to two scFv (single-chain antibodies), the binding of anantibody to streptavidin, and introduction of a helix-turn-helix motif.

The antibody of the present invention may also be a polyclonal antibodythat is a mixture of multiple types of anti-GARP antibodies havingdifferent amino acid sequences. An example of the polyclonal antibodycan be a mixture of multiple types of antibodies having different CDRs.As such a polyclonal antibody, an antibody obtained by culturing amixture of cells producing different antibodies and then purifying theobtained culture can be used (see WO2004/061104).

As a modification of the antibody, an antibody binding to various typesof molecules such as polyethylene glycol (PEG) can be used.

The antibody of the present invention may further be a conjugate formedby such an antibody and another drug (Immunoconjugate). Such an antibodycan be, for example, an antibody that binds to a radioactive substanceor a compound having pharmacological action (Nature Biotechnology (2005)23, p. 1137-1146). Examples of such an antibody can include Indium(¹¹¹In) Capromab pendetide, Technetium (^(99m)Tc) Nofetumomab merpentan,Indium (¹¹¹In) Ibritumomab, Yttrium (⁹⁰Y) Ibritumomab, and Iodine (¹³¹I)Tositumomab.

3. Medicament Containing Anti-GARP Antibody

Since the antibody obtained by the method described in the above section“2. Production of anti-GARP antibody” exhibits cytotoxicity on Treg, itcan be used as a medicament, and in particular, as a therapeutic agentfor cancer and infectious disease (in particular, malaria and HIVinfection).

Cytotoxicity caused by an antibody in vitro can be measured based on theactivity of suppressing the proliferative responses of cells.

For example, a cancer cell line overexpressing GARP is cultured, andantibodies having different concentrations are added to the culturesystem. Thereafter, the inhibitory activity of the antibody on focusformation, colony formation and spheroid growth can be measured.

The in vivo therapeutic effects of an antibody on the cancer of anexperimental animal can be measured, for example, by administering theantibody to a nude mouse into which a tumor cell line overexpressingGARP has been transplanted, and then measuring a change in the cancercells.

Examples of the cancer type can include lung cancer, kidney cancer,urothelial cancer, colon cancer, prostate cancer, glioblastomamultiforme, ovarian cancer, pancreatic cancer, breast cancer, melanoma,liver cancer, bladder cancer, stomach cancer, esophageal cancer, andblood cancer. However, the cancer type is not limited to theaforementioned examples, as long as the cancer cells, as therapeutictargets, express GARP.

As a substance used in a medicament acceptable for the pharmaceuticalcomposition of the present invention, a substance that is non-toxic to asubject, to whom the pharmaceutical composition is to be administered,is preferable, in terms of an applied dose or an applied concentration.

The pharmaceutical composition of the present invention can comprise apharmaceutical substance for altering or retaining pH, osmotic pressure,viscosity, transparency, color, isotonicity, sterility, stability,solubility, sustained release rate, absorptivity, and permeability.Examples of the pharmaceutical substance can include the followingsubstances, but are not limited thereto: amino acids such as glycine,alanine, glutamine, asparagine, arginine or lysine; antibacterialagents; antioxidants such as ascorbic acid, sodium sulfate or sodiumhydrogen sulfite; buffers such as a phosphate, citrate or borate buffer,sodium hydrogen carbonate, or a Tris-HCl solution; fillers such asmannitol or glycine; chelating agents such as ethylenediaminetetraaceticacid (EDTA); complexing agents such as caffeine, polyvinylpyrrolidine,β-cyclodextrin or hydroxypropyl-β-cyclodextrin; bulking agents such asglucose, mannose or dextrin; other carbohydrates such as monosaccharidesor disaccharides; a coloring agent; a flavor agent; a diluent; anemulsifier; hydrophilic polymers such as polyvinylpyrrolidine; alow-molecular-weight polypeptide; salt-forming counterions; antisepticssuch as benzalkonium chloride, benzoic acid, salicylic acid, thimerosal,phenethyl alcohol, methylparaben, propylparaben, chlorhexidine, sorbicacid or hydrogen peroxide; solvents such as glycerin, propylene glycolor polyethylene glycol; sugar alcohols such as mannitol or sorbitol;polysorbates such as a suspending agent, sorbitan ester, polysorbate 20or polysorbate 80; surfactants such as Triton, tromethamine, lecithin orcholesterol; stability enhancers such as sucrose or sorbitol; asuspending agent; elasticity enhancers such as sodium chloride,potassium chloride, mannitol or sorbitol; transporting agents;excipients; and/or pharmaceutical adjuvants. Such a pharmaceuticalsubstance is preferably added to an anti-GARP antibody in an amount of0.001 to 100 times, in particular, 0.1 to 10 times higher than theweight of the anti-GARP antibody. The preferred composition of apharmaceutical composition in a formulation can be determined, asappropriate, by a person skilled in the art, depending on the targetdisease, the applied administration route, etc.

An excipient or a carrier in the pharmaceutical composition may be aliquid or a solid. A suitable excipient or carrier may be water forinjection, normal saline, an artificial cerebrospinal fluid, or othersubstances commonly used in parenteral administration. Neutral normalsaline or normal saline comprising serum albumin can also be used as acarrier. The pharmaceutical composition can comprise a Tris buffer withpH 7.0-8.5, an acetate buffer with pH 4.0-5.5, or a citrate buffer withpH 3.0-6.2. In addition, these buffers can also comprise sorbitol orother compounds.

Examples of the pharmaceutical composition of the present invention caninclude a pharmaceutical composition comprising an anti-GARP antibodyand a pharmaceutical composition comprising an anti-GARP antibody and atleast one cancer therapeutic agent. The pharmaceutical composition ofthe present invention is prepared as a drug having a selectedcomposition and a necessary purity in the form of a freeze-dried productor a liquid. Such a pharmaceutical composition comprising an anti-GARPantibody and a pharmaceutical composition comprising an anti-GARPantibody and at least one cancer therapeutic agent can also be moldedinto a freeze-dried product comprising a suitable excipient such assucrose.

A cancer therapeutic agent comprised, together with an anti-GARPantibody, in the above described pharmaceutical composition may beadministered to an individual, simultaneously, separately, orcontinuously, together with the anti-GARP antibody. Otherwise, thecancer therapeutic agent and the anti-GARP antibody may each beadministered to the subject at different administration intervals.Examples of such a cancer therapeutic agent can include abraxane,carboplatin, cisplatin, gemcitabine, irinotecan (CPT-11), paclitaxel,pemetrexed, sorafenib, vinblastin, the drugs described in InternationalPublication No. WO2003/038043, LH-RH analogs (leuprorelin, goserelin,etc.), estramustine-phosphate, estrogen antagonists (tamoxifen,raloxifene, etc.), and aromatase inhibitors (anastrozole, letrozole,exemestane, etc.). However, examples of the cancer therapeutic agent arenot limited to the above described drugs, as long as the agents haveantitumor activity.

The subject to be the target for administration is not particularlylimited. It is preferably a mammal, and more preferably a human.

The pharmaceutical composition of the present invention can be preparedfor use in parenteral administration, or for use in gastrointestinalabsorption involving oral administration. The composition andconcentration of a formulation can be determined depending on theadministration method. With regard to the affinity of an anti-GARPantibody comprised in the pharmaceutical composition of the presentinvention for GARP, namely, the dissociation constant (Kd value) of theanti-GARP antibody to GARP, as the affinity increases (i.e., the Kdvalue is low), the pharmaceutical composition can exhibit medicinaleffects, even if the applied dose thereof to a human is decreased. Basedon these results, the applied dose of the pharmaceutical composition ofthe present invention to a human can also be determined. When ahuman-type anti-GARP antibody is administered to a human, the antibodymay be administered at a dose of from about 0.001 to 100 mg/kg once orseveral times at intervals of 1 to 180 days. Examples of the form of thepharmaceutical composition of the present invention can include aninjection including a drip infusion, a suppository, a transnasal agent,a sublingual agent, and a transdermal absorption agent.

Hereinafter, the present invention will be specifically described in thefollowing examples. However, these examples are not intended to limitthe scope of the present invention.

EXAMPLES

In the following examples, unless otherwise specified, individualoperations regarding genetic manipulation have been carried outaccording to the method described in “Molecular Cloning” (Sambrook, J.,Fritsch, E. F. and Maniatis, T., published by Cold Spring HarborLaboratory Press in 1989) or other methods described in experimentalmanuals used by persons skilled in the art, or when commerciallyavailable reagents or kits have been used, the examples have beencarried out in accordance with the instructions included in thecommercially available products.

Hereinafter, the present invention will be specifically described in thefollowing examples. However, these examples are not intended to limitthe scope of the present invention.

Example 1: Obtaining Antibody 1)-1 Separation of Anti-GARP Fab byPanning in Phage Display

An n-CoDeR Fab phage library (BioInvent) was used in separation of Fabbinding to GARP. Using EZ-Link NHS-Chromogenic-Biotin reagent (ThermoScientific), GARP (R&D Systems) was biotinylated. For liquid-phasepanning, the biotinylated GARP was solid-phased on DynabeadsStreptavidin M-280 (Life Technologies), and phages were then added.Unbound phages were removed by a washing operation using a magnet(DynaMag-2, Life Technologies). Thereafter, GARP-bound phages werecollected by treating them with trypsin (Sigma-Aldrich), and were thenamplified using Escherichia coli. In total, panning operations werecarried out three times, and, using restriction enzymes, a DNA fragmentencoding Fab was cut from a polyclonal phagemid, and was then loaded onan expression vector for Escherichia coli. Thereafter, Escherichia coliTOP100F′ (Life Technologies) was transformed with the expression vector,and Fab was then allowed to express in the presence of IPTG(Sigma-Aldrich). The obtained Fab was subjected to screening by ELISA.

1)-2 Screening for GARP-Binding Fab by ELISA

50 μL GARP, which had been diluted to 2 μg/mL with PBS (0.01 M phosphatebuffered saline (pH 7.4) containing 0.138 M sodium chloride and 0.0027 Mpotassium chloride; Sigma-Aldrich), was added to each well of a 384-wellMaxi-sorp plate (Black, Nunc), and it was then incubated overnight at 4°C. for coating the plate. Alternatively, 50 μL of NeutrAvidin (LifeTechnologies) which had been diluted to 1 μg/mL with PBS was added tosuch a 384-well Maxi-sorp plate for coating the plate (by incubatingovernight at 4° C.). Thereafter, the plate was washed with an ELISAbuffer (PBS (Sigma-Aldrich) supplemented with 0.05% Tween-20 (Bio-RAD))three times, and biotinylated GARP was then added thereto (1 pmol/50 μLPBS/well), followed by incubation at room temperature for 1 hour withmixing. The plate was washed with ELISA buffer three times, was thenblocked with Blocker Casein (Thermo Scientific), and was further washedwith the ELISA buffer three times. Thereafter, a culture supernatantcontaining Fab produced by Escherichia coli was added, and the plate wasthen incubated at room temperature for 1 hour with mixing. The plate waswashed with the ELISA buffer three times, and 50 μL of 2500-fold dilutedHorseradish peroxidase (HRP)-labeled anti-human F (ab′)₂ antibody (R&DSystems) was added. The plate was further incubated at room temperaturefor 1 hour with mixing. The reaction mixture was washed with the ELISAbuffer three times, and SuperSignal Pico ELISA Chemiluminescentsubstrate (Thermo Scientific) was then added to the wells. Ten minuteslater, chemiluminescence was measured using a plate reader (Envision2104 Multilabel Reader, Perkin Elmer), and GARP-bound Fab was isolated.

1)-3 Determination of Nucleotide Sequence of ELISA-Positive Clone

The heavy chain and light chain variable regions of ELISA-positiveclones (105F and 110F) were analyzed by a Dye Terminator method (BigDye(registered trademark) Terminator v3.1, Life Technologies). Thesequences of the main primers used in sequencing are as follows.

Primer A:  (SEQ ID NO: 10) 5′-GAA ACA GCT ATG AAA TAC CTA TTG C-3′Primer B:  (SEQ ID NO: 11) 5′-GCC TGA GCA GTG GAA GTC C-3′ Primer C: (SEQ ID NO: 12) 5′-TAG GTA TTT CAT TAT GAC TGT CTC-3′ Primer D: (SEQ ID NO: 13) 5′-CCC AGT CAC GAC GTT GTA AAA CG-3′

As a result of the above described analysis, the nucleotide sequences ofthe variable regions of the 105F antibody and 110F antibody genes weredetermined.

The nucleotide sequence of the heavy chain variable region of the 105Fantibody was a sequence consisting of the nucleotides at nucleotidepositions 1 to 354 in the nucleotide sequence shown in SEQ ID NO: 6 inthe sequence listing, and the nucleotide sequence of the light chainvariable region of the 105F antibody was a sequence consisting of thenucleotides at nucleotide positions 1 to 336 in the nucleotide sequenceshown in SEQ ID NO: 7 in the sequence listing.

The nucleotide sequence of the heavy chain variable region of the 110Fantibody was a sequence consisting of the nucleotides at nucleotidepositions 1 to 369 in the nucleotide sequence shown in SEQ ID NO: 8 inthe sequence listing, and the nucleotide sequence of the light chainvariable region of the 110F antibody was a sequence consisting of thenucleotides at nucleotide positions 1 to 333 in the nucleotide sequenceshown in SEQ ID NO: 9 in the sequence listing.

1)-4: Preparation of Full-Length IgG, and Expression and Purification ofIgG

Full-length IgG of ELISA-positive clones including 105F and 110F wasprepared by the following method.

A nucleotide sequence encoding Fab was determined, and thereafter,nucleotide sequences corresponding to the variable regions of the heavychain and light chain of each antibody specified in the above 1)-3 werespecified.

According to a common method, the nucleotide sequence of the variableregion of the above described heavy chain was ligated to a nucleotidesequence encoding the constant region of the heavy chain of human IgG₁(CH1+Fc region: the amino acid sequence at amino acid positions 119 to448 in the amino acid sequence shown in SEQ ID NO: 2 in the sequencelisting), and also, the nucleotide sequence of the variable region ofthe above described light chain was ligated to a nucleotide sequenceencoding the constant region of the light chain of human IgG₁ (CL: theamino acid sequence at amino acid positions 113 to 217 in the amino acidsequence shown in SEQ ID NO: 3 in the sequence listing). Thereafter, theobtained ligate was inserted into an expression vector for animal cells,such as pcDNA3.3 (Invitrogen), to construct an IgG expression vector foranimal cells.

The nucleotide sequence of the constructed IgG expression vector wasanalyzed again, so that it was confirmed that the nucleotide sequence ofthe full-length heavy chain of the 105F antibody was the nucleotidesequence shown in SEQ ID NO: 6 in the sequence listing, and that thenucleotide sequence of the full-length light chain of the 105F antibodywas the nucleotide sequence shown in SEQ ID NO: 7 in the sequencelisting.

It was also confirmed that the nucleotide sequence of the full-lengthheavy chain of the 110F antibody was the nucleotide sequence shown inSEQ ID NO: 8 in the sequence listing, and that the nucleotide sequenceof the full-length light chain of the 110F antibody was the nucleotidesequence shown in SEQ ID NO: 9 in the sequence listing.

Moreover, based on the above described nucleotide sequences, the aminoacid sequences of the full-length heavy chain and full-length lightchain of the 105F antibody encoded by the nucleotide sequences, and theamino acid sequences of the full-length heavy chain and full-lengthlight chain of the 110F antibody encoded by the nucleotide sequences,were determined.

The amino acid sequence of the heavy chain of the 105F antibody was theamino acid sequence shown in SEQ ID NO: 2 in the sequence listing, andthe amino acid sequence of the light chain thereof was the amino acidsequence shown in SEQ ID NO: 3 in the sequence listing.

The amino acid sequence of the heavy chain of the 110F antibody was theamino acid sequence shown in SEQ ID NO: 4 in the sequence listing, andthe amino acid sequence of the light chain thereof was the amino acidsequence shown in SEQ ID NO: 5 in the sequence listing.

The IgG of the 105F antibody or the 110F antibody was transientlyexpressed by inserting the above described IgG expression vector foranimal cells into FreeStyle 293F cells (Life Technologies), and then theresulting IgGs were purified using a Protein A Affinity column (HiTrapMab Select SuRe, GE Healthcare), as necessary. Thereafter, the buffer inwhich IgG was dissolved was replaced with PBS using Vivaspin 20 (7kMWCO, GE Healthcare) and the resultant was then subjected to thefollowing step “1)-5.”

1)-5 Confirmation of Binding of Purified IgG to GARP According to ELISA

100 μL of human GARP (R&D Systems, catalog number: 6055-LR) diluted to 1μg/mL with PBS was added to each well of a 96-well Maxi-sorp plate(Black, Nunc), and the plate was then incubated overnight at 4° C. forcoating the plate.

The plate was washed with ELISA buffer three times, and then blockedwith Blocker Casein at room temperature for 1 hour. The plate was washedwith the ELISA buffer three times, and 100 μL of 50 nM 105F antibody, 50nM 110F antibody, 50 nM human IgG (Jackson Immuno Research), 50 nM mouseanti-GARP antibody (Plato-1, ENZO Life Science) or 50 nM mouse IgG(Jackson Immuno Research) was added to the wells, and the plate wasincubated at room temperature for 1 hour with mixing.

The plate was washed with the ELISA buffer three times. After that, 100μL of HRP-labeled anti-human Fc antibody (R&D Systems), which had been5000-fold diluted with PBS, was added to wells treated with 105Fantibody, 110F antibody or human IgG. On the other hand, 100 μL ofHRP-labeled anti-mouse Fc antibody (R&D Systems), which had been5000-fold diluted with PBS, was added to the wells treated with mouseanti-GARP antibody and mouse IgG. The plate was incubated at roomtemperature for 1 hour with mixing.

The plate was washed with the ELISA buffer five times, and 0.1 mL ofSuperSignal Pico ELISA Chemiluminescent substrate was then added to thewells. Ten minutes later, chemiluminescence was measured using a platereader (Envision 2104 Multilabel Reader, Perkin Elmer).

As a result, it was demonstrated that the 105F antibody and the 110Fantibody bound to GARP (FIG. 10) as commercially available anti-GARPantibody did.

Example 2: Binding to Antigen Gene-Expressing Cells

Regarding a GARP expression vector, a cDNA clone of human GARP (Origene)was purchased, and it was then cloned into a pcDNA3.1 (+) vector(Invitrogen) according to a common method. Thereafter, the nucleotidesequence thereof was confirmed.

The GARP expression vector and a pcDNA3.1 vector used as a control wereeach transfected into HEK-293T cells (ATCC: CRL-11268), usingLipofectamine 2000 (Invitrogen). The resulting cells were cultured in aDMEM medium (Invitrogen) supplemented with 10% fetal bovine serum (FBS,Hyclone) overnight in 5% CO₂ at 37° C. Thereafter, the cells wereharvested from the plate by TrypLE Express (Invitrogen) treatment, andthe cells were washed with MACS buffer (PBS containing 0.5% BSA and 2 mMEDTA; Miltenyi Biotec) twice and were then suspended in the samesolution as described above. The 105F antibody and control human IgG(ENZO Life Science) were each added to the cell suspension, and thecells were incubated for 15 minutes at 4° C. The cells were washed twicewith MACS buffer. Fluorescein isothiocyanate (FITC)-labeled anti-IgGantibody (Jackson ImmunoResearch Laboratories) was added and suspended,and the cells were further incubated at 4° C. for 15 minutes. The cellswere washed twice with MACS buffer, and the cells were then fixed with1% PFA (prepared from Paraformaldehyde 32% solution (ELECTRON MICROSCOPYSCIENCES)), and measured by using a flow cytometer (FACS Canto II;Becton Dickinson). The data was analyzed using Flowjo (TreeStar). Deadcells were removed from the analysis by gating out cells stained withHorizon FVS450 (Becton Dickinson). Thereafter, a histogram of the FITCfluorescence intensity of live cells was generated.

In terms of HEK-293T cells transfected with the control vector alone ahistogram of fluorescence intensity for the 105F antibody was similar tothat for the control IgG. On the other hand, in terms of GARP-expressingHEK-293T cells, it was confirmed that the histogram for the 105Fantibody shifted to a strong fluorescence intensity side, in comparisonto the histogram for the control IgG (FIG. 11). From the aforementionedresults, it was found that the 105F antibody specifically bound to GARPexpressed by HEK-293T cells.

Example 3: Binding to Endogenous GARP-Expressing Cells

3)-1 Flow cytometric analysis using L428 cells A fluorescent-labeledform of the 105F antibody was prepared using an Alexa Fluor 647monoclonal antibody labeling kit (Invitrogen). L428 cells (obtained fromDSMZ) were washed twice with MACS buffer, and were suspended in the samesolution. The labeled 105F antibody was added to the cell suspension,and the cells were incubated for 30 minutes at 4° C. The cells werewashed twice with MACS buffer, and the cells were then fixed with 1%PFA, and measured by using a flow cytometer (FACS Canto II, BectonDickinson). The data was analyzed using FlowJo (TreeStar). Dead cellswere removed by gating out cells stained with Horizon FVS450.Thereafter, a histogram of the FITC fluorescence intensity of live cellswas generated. In comparison to the histogram of fluorescence intensityfor L428 cells alone, the histogram of L428 cells to which the 105Fantibody had been added shifted to the strong fluorescence intensityside. Thus, it was confirmed that the 105F antibody bound to GARPendogenously expressed by the cells (FIG. 12).

3)-2 Flow Cytometric Analysis Using Human Treg

Peripheral blood mononuclear cells (PBMC) from a healthy subject wereseparated using Ficoll-Paque PLUS (GE Healthcare), and the separatedcells were then seeded at 2×10⁶ cells/mL in RPMI1640 medium (Invitrogen)supplemented with 10% FBS (hereinafter referred to as “RP-F10 medium”)in a low-adhesion 24-well plate (Costar). An anti-CD3 antibody (BDPharmingen) and an anti-CD28 antibody (BD Pharmingen) were added to thewells, and the cells were cultured for 20 hours. Thereafter, the cellswere suspended in FACS buffer (HBSS (Invitrogen) supplemented with 10 mMHEPES (Invitrogen), 2 mM EDTA (Invitrogen), and 2% FBS), and the labeled105F antibody prepared in the above 3)-1 and an Alexa Fluor 647-labeledanti-GARP antibody (G14D9, eBioscience) were added to the suspension.The cells were incubated on ice for 30 minutes. The cells were washedwith FACS buffer, and Fixation/Permeabilization working solution(eBioscience) was added. The cells were further incubated on ice for 30minutes, and the cells were washed with Permeabilization buffer(eBioscience). After that, 2% rat serum (eBioscience) was added to thecells. The cells were incubated at room temperature for 15 minutes, andPE-labeled anti-Foxp3 antibody (eBioscience) was added, followed byfurther incubation at room temperature for 30 minutes. The cells werewashed and fixed with a tissue-fixing solution which was prepared bytwo-fold diluting 4% Paraformaldehyde phosphate buffer solution (WakoPure Chemical Industries, Ltd.) with D-PBS (Invitrogen) at 4° C. for 15minutes or more. After the cells were washed with the FACS buffer, thecells were measured by using a flow cytometer (FACS Canto II; BectonDickinson) and were analyzed using FlowJo (Tree Star). As a result, the105F antibody bound to FoxP3-positive Treg as commercially availableanti-GARP antibody did (FIG. 13).

Example 4: Properties of Anti-GARP Antibody 4)-1 ADCC Activity 4)-1-1Preparation of Effector Cells

Frozen human PBMC (Cellular Technology) was thawed in accordance withthe protocols. NK cells were purified from the PBMC, using an NK cellisolation kit (Miltenyi Biotec). The obtained NK cells were incubatedovernight in an RP-F10 medium supplemented with 100 IU/mL rhIL-2(Novartis). Thereafter, the number of live cells was counted by a trypanblue-exclusion test, and the cells were then re-suspended in an RP-F10medium at a cell density of 2×10⁵ cells/mL. The obtained cells were usedas effector cells.

4)-1-2 Preparation of Target Cells

30 μL (1110 kBq) of Chromium-51 (⁵¹Cr) was mixed with 0.6×10⁶ L428 cellsdescribed in Example 3)-1, in RPMI1640 medium (Invitrogen) supplementedwith 10% FBS, and the cells were incubated for 2 hours in 5% CO₂ at 37°C., so that the cells were radio-labeled. The labeled cells were washedthree times with RPMI1640 medium (Invitrogen) supplemented with 10% FBS,and the cells were then re-suspended in the same medium at 4×10⁴cells/mL. The obtained cells were used as target cells.

4)-1-3 ⁵¹Cr Release Assay

The 105F antibody, which had been diluted with an RP-F10 medium so thatfinal concentration would be at 1, 10, 100, or 1000 ng/mL, was dispensedin an amount of 50 μL/well into a 96-well U-bottom microplate (Costar),and the target cells were added to the wells (50 μL/well). The plate wasincubated at 4° C. for 30 minutes. Subsequently, the effector cells wereadded to the wells (100 μL/well), and the plate was incubated in 5% CO₂at 37° C. for 4 hours. Thereafter, 50 μL/well of supernatant wascollected and applied to LumaPlate (PerkinElmer), and the releasedgamma-ray dose was measured by using a gamma counter. The cell lysisrate caused by ADCC activity was calculated according to the followingformula.

Cell lysis rate (%)=(A−B)/(C−B)×100

A: Count of sample wellB: Mean value (n=3) of count of spontaneous release (well withoutantibody and effector cells). Upon addition of the antibody and uponaddition of the effector cells, 50 μL and 100 μL of RP-F10 media wereadded, respectively. The same operations as those for the sample wellswere carried out other than the above.C: Mean value (n=3) of count of maximum release (well in which thetarget cells were dissolved with a surfactant). Upon addition of theantibody, 50 μL of RP-F10 medium was added. Upon addition of theeffector cells, 100 μL of RP-F10 medium supplemented with 2% (v/v)Triton-X100 (Sigma) was added. The same operations as those for thesample wells were carried out other than the above.

The results are shown in FIG. 14. The 105F antibody exhibited cytolyticactivity on L428 cells in an antibody concentration dependent manner. Onthe other hand, the control human IgG did not exhibit such cytolyticactivity. Thus, the 105F antibody had ADCC activity on L428 cellsexpressing endogenous GARP. It is to be noted that the human IgG1anti-GARP antibodies (MHG8 and LHG10) produced based on the sequenceinformation described in Patent Literature 1 did not exhibit ADCCactivity.

4)-2 Inhibitory Activity to Treg Function 4)-2-1 Preparation of Treg,Teff (Effector T Cells: CD4-Positive CD25-Negative Helper T Cells), andAccessory Cells

CD4-positive T cells were separated from PBMC that were prepared in thesame manner as in the above 4)-1-1, using CD4 T cell ISOLATION Kit(Miltenyi Biotec), and an FITC-labeled anti-CD4 antibody (MiltenyiBiotec) and an APC-labeled anti-CD25 antibody (Miltenyi Biotec) wereadded to the CD4-positive T cells. The cells were incubated at 4° C. for30 minutes. After the cells were washed, the cells were suspended inMACS buffer, and CD4-positive CD25-negative cells (Teff) andCD4-positive CD25-strongly-positive cells (Treg) were separated usingFACS Aria IIu (Becton Dickinson).

On the other hand, CD3-positive cells were removed from PBMC using CD3Microbeads (Miltenyi Biotec) and the cells were irradiated at a dose of1 C/kg (absorbed dose: 38.76 Gy/kg (3876 Rad/kg)) using an X-rayirradiator (Hitachi Medical Corporation) to prepare accessory cells.

4)-2-2 Co-Culture Method and Assay for Inhibitory Activity to TregFunction

As a culture medium, RPMI1640 medium (Invitrogen) supplemented withPenicillin and Streptomycin (Invitrogen), 1×MEM NEAA (Invitrogen), 1×Sodium pyruvate (Invitrogen), 5 mM Hepes and 5% Human male AB serum(Sigma) was used. Teff (2000 cells/well) and accessory cells (20000cells/well) were mixed and added into each well of a 96-well U-bottommicroplate, and Treg were further added and seeded to wells at 500cells/well. In addition, control wells without Treg were also prepared.An anti-CD3 antibody, an anti-CD28 antibody, and a 105F antibody wereadded to the wells at a final concentration of 50 or 10 μg/mL, and theplate was incubated for 5 days in 5% CO₂ at 37° C. Thereafter,[³H]-thymidine (PerkinElmer) at 18.5 kBq/mL was prepared, and added toeach well at 20 μL/well. The cells were further incubated for 18 hours.The cells were harvested in Filtermat A (PerkinElmer) by using a cellharvester (Mach II, Tomtech), and the radioactivity of [³H]-thymidineincorporated into the cells was measured using a scintillation counter(MicroBeta, PerkinElmer). The measured data were expressed as correctedcount per minute (CCPM).

Human IgG1 anti-GARP antibodies (MHG8 and LHG10) produced based on thesequence information described in Patent Literature 1 were alsosubjected to the present experiment system.

4)-2-3 Calculation of Inhibitory Activity

A mean value of three wells under individual co-culture conditions wascalculated. Diminished value of proliferation in co-culturing Teff withTreg when compared with that of Teff alone, was defined as a“Suppression rate of Teff proliferation caused by Treg” (=1−[CCPM ofco-culture/CCPM of Teff alone]).

The inhibitory activity of each antibody to the Treg function wasdetermined by subtracting suppression rate of Teff proliferation by Tregin the presence of antibody from that in the absence of antibody(=[suppression rate upon non-addition of the antibody]−[suppression rateupon addition of each antibody]). It is to be noted that this inhibitoryactivity of a sample is calculated every time in each experiment.

The results of the inhibitory activity of the 105F antibody to the Tregfunction at 50 μg/mL (inhibitory rate: 72.6%) are shown in FIG. 15, andthe results of the 105F antibody and the MHG-8 and LHG-10 antibodies (10μg/mL each) are shown in FIG. 16. The MHG-8 and LHG-10 antibodies didnot have inhibitory activity to the Treg function (inhibitory rates:0.8% and 0.0%, respectively), whereas the 105F antibody significantlyinhibited Treg function (inhibitory rate: 65.8%). The inhibitory ratecaused by transducing siRNA to GARP into Treg was about 15%, whencalculated roughly by using values in FIG. 5A (CD4+CD25−(Teff):Treg=4:1)of Non Patent Literature 10.

Example 5: Production of Rat Antibody 5)-1 Preparation of GARPExpression Vector

The expression vector described in Example 2 was used as a GARPexpression vector, and an EndoFree Plasmid Giga Kit (QIAGEN) was usedfor mass production.

5)-2 Immunization of Rats

For immunization, WKY/Izm female rats (Japan SLC, Inc.) were used.First, the lower limbs of each rat were pre-treated with Hyaluronidase(SIGMA-ALDRICH) and a GARP expression vector was intramuscularlyinjected into the same sites. Subsequently, employing ECM830 (BTX), invivo electroporation was performed on the same sites using two-needleelectrode. Once every two weeks, the same in vivo electroporation wasrepeated, and lymph nodes or spleen was collected from the rat, and wasused in production of hybridomas.

5)-3 Production of Hybridomas

The lymph nodes or splenic cells were fused with mouse myelomaSP2/0-ag14 cells (ATCC, No. CRL-1581) according to electrical cellfusion, using LF301 Cell Fusion Unit (BEX), and the cells were thendiluted with ClonaCell-HY Selection Medium D (StemCell Technologies) andincubated. Hybridoma colonies that appeared in culture were picked andselected as monoclonal hybridomas. Every hybridoma colony was cultured,and culture supernatant from each hybridoma was used to screen foranti-GARP antibody-producing hybridomas.

5)-4 Antibody Screening According to Cell-ELISA Method 5)-4-1Preparation of Antigen Gene-Expressing Cells for Use in Cell-ELISA

293α cells (a stable expression cell line derived from HEK-293 cells(ATCC: CRL-1573) expressing integrin αv and integrin β3) were preparedat 7.5×10⁵ cells/mL in DMEM medium (Invitrogen) supplemented with 10%FBS. In accordance with transduction procedures for using Lipofectamine2000 (Life Technologies), a GARP expression vector or a pcDNA3.1 (+)vector used as a negative control was transfected into the cells, andthe cells were dispensed in an amount of 50 μl each to a 96-Half areawell plate (Corning). Thereafter, the cells were cultured in DMEM mediumsupplemented with 10% FBS for 24 to 27 hours in 5% CO₂ at 37° C. Theobtained transfected cells were used for Cell-ELISA in an adhesivestate.

5)-4-2 Cell-ELISA

The culture supernatant of the 293α cells transfected with expressionvectors prepared in Example 5)-4-1 was removed, and culture supernatantfrom each hybridoma was added to the 293α cells transfected either withGARP expression vector or pcDNA3.1 (+) vector. The cells were incubatedat 4° C. for 1 hour. The cells in the wells were washed once with PBS(+) supplemented with 5% FBS, and thereafter, Anti-Rat IgG-Peroxidaseantibody produced in rabbits (SIGMA) that had been 500-fold diluted withPBS (+) supplemented with 5% FBS was added to the wells. The cells wereincubated at 4° C. for 1 hour. The cells in the wells were washed threetimes with PBS (+) supplemented with 5% FBS, and OPD coloring solution(which had been prepared by dissolving o-phenylenediaminedihydrochloride (Wako Pure Chemical Industries, Ltd.) and H₂O₂ in an OPDsolution (0.05 M trisodium citrate, 0.1 M disodium hydrogen phosphate12-water; pH 4.5), so that the substances became 0.4 mg/ml and 0.6%(v/v), respectively) was added in an amount of 50 μl/well to the wells.While the plate was incubated with mixing for a time, a coloringreaction was carried out. Thereafter, 1M HCl was added to the plate (50μl/well) to terminate the coloring reaction, and the absorbance at 490nm was measured using a plate reader (ENVISION: PerkinElmer). In orderto select hybridomas that produce an antibody specifically binding tohuman GARP expressed on the surface of a cell membrane, hybridomas thatproduced a culture supernatant exhibiting higher absorbance in 293αcells transfected with GARP expression vector than that in cellstransfected with the control pcDNA3.1 (+)vector were selected aspositive cells that produce anti-human GARP antibody.

5)-5 Antibody Screening According to Flow Cytometric Method 5)-5-1Preparation of Antigen Gene-Expressing Cells for Use in Flow CytometricAnalysis

HEK-293T cells (obtained from ATCC) were seeded in a 225-cm² flask(Sumitomo Bakelite Co., Ltd.) at 5×10⁴ cells/cm², and the cells werethen cultured in DMEM medium supplemented with 10% FBS overnight in 5%CO₂ at 37° C. On the following day, HEK-293T cells were transfected witha GARP expression vector or a pcDNA3.1 (+) vector used as a negativecontrol using Lipofectamine 2000, and the cells were further incubatedovernight in 5% CO₂ at 37° C. On the following day, the transfectedHEK-293T cells were treated with TrypLE Express (Life Technologies),were washed with DMEM medium supplemented with 10% FBS, and werere-suspended in PBS supplemented with 5% FBS. The obtained cellsuspension was used in a flow cytometric analysis.

5)-5-2 Flow Cytometric Analysis

The binding specificity to human GARP of an antibody produced fromhybridomas that had been determined to be positive by Cell-ELISA inExample 5)-4-2 was further confirmed by a flow cytometric analysis.

A suspension of the transiently expressing HEK-293T cells prepared inExample 5)-5-1 was centrifuged, and a supernatant was then removed.Thereafter, culture supernatant from each hybridoma was added to cellsand suspended. The cells were incubated at 4° C. for 1 hour. The cellswere washed twice with PBS supplemented with 5% FBS, and FITC-conjugatedanti-Rat IgG (SIGMA) that had been 500-fold diluted with PBSsupplemented with 5% FBS was added to the cells and suspended. The cellswere incubated at 4° C. for 1 hour. The cells were washed twice with PBSsupplemented with 5% FBS, and were then re-suspended in PBS supplementedwith 5% FBS and 2 μg/ml 7-aminoactinomycin D (Molecular Probes). Thecells were measured using a flow cytometer (FC500: manufactured byBeckman Coulter). The data was analyzed using Flowjo (TreeStar). Afterdead cells were removed from analysis by gating out 7-AminoactinomycinD-positive cells, a histogram of the FITC fluorescence intensity of livecells was generated. Hybridomas producing human GARP-binding antibodies(113 clones) were selected based on results where the histogram for theantibody shifted to the strong fluorescence intensity side in HEK-293Tcells transfected with GARP-expressing vector compared with cellstransfected with control pcDNA3.1 vector.

5)-6 Preparation of Monoclonal Antibody 5)-6-1 Culture of Hybridomas151D and 198D

From the rat anti-human GARP antibody-producing hybridomas obtained inthe above 5)-5-2, hybridomas 151D and 198D, which had been suggested tobind strongly to human GARP, were selected.

A rat anti-GARP monoclonal antibody was purified from a hybridomaculture supernatant.

First, the volume of rat anti-GARP monoclonal antibody-producinghybridomas was sufficiently increased with ClonaCell-HY Selection MediumE, and thereafter, the medium was exchanged with Hybridoma SFM (LifeTechnologies) to which 20% of Ultra Low IgG FBS (Life Technologies) hadbeen added. Thereafter, the hybridomas (8 to 9×10⁷ cells) were seeded ina 1272-cm² flask (Corning), and were then cultured for 7 days. Thepresent culture supernatant was harvested by centrifugation, and it wassterilized by passing through a 0.8-μm filter, and through a 0.45-μmfilter (Corning).

5)-6-2 Purification of Monoclonal Antibody

An antibody was purified from the culture supernatant of hybridomasprepared in Example 5)-6-1 according to Protein G affinitychromatography. The antibody was adsorbed on a Protein G column (GEHealthcare Bioscience), the column was then washed with PBS, and theantibody was then eluted with a 0.1 M glycine/HCl aqueous solution (pH2.7). 1 M Tris-HCl (pH 9.0) was added to the eluant, so that the pH wasadjusted to pH 7.0 to 7.5. Thereafter, the solution was dialyzed (ThermoScientific, Slide-A-Lyzer Dialysis Cassette), so that the buffer wasreplaced with PBS. Using Centrifugal UF Filter Device VIVASPIN20(molecular weight cutoff: UF30K, Sartorius), the antibody wasconcentrated, so that the concentration of the antibody was adjusted to0.7 mg/mL or more. Finally, the antibody was filtrated through aMinisart-Plus filter (Sartorius) to obtain a purified sample.

Example 6: Cloning of Rat Antibody and Production of Human ChimericAntibody

6)-1 Cloning and Sequencing of cDNA of Rat Antibody 151D6)-1-1 Preparation of Total RNA from 151D-Producing Hybridomas

In order to amplify cDNA comprising the variable region of 151D, totalRNA was prepared from 151D-producing hybridomas using TRIzol Reagent(Ambion).

6)-1-2 Amplification of cDNA Comprising 151D Heavy Chain Variable RegionAccording to 5′-RACE PCR, and Sequencing Thereof

cDNA comprising a heavy chain variable region was amplified usingapproximately 1 μg of the total RNA prepared in Example 6)-1-1 and aSMARTer RACE cDNA Amplification Kit (Clontech).

As primers used to amplify the cDNA of the variable region of a 151Dheavy chain gene according to PCR, UPM (Universal Primer A Mix: includedwith SMARTer RACE cDNA Amplification Kit) and primers designed from thesequences of the constant regions of known rat heavy chains were used.

cDNA comprising the variable region of the heavy chain amplified by5′-RACE PCR was cloned into a plasmid, and thereafter, the nucleotidesequence of the cDNA of the heavy chain variable region was subjected tosequence analysis.

The determined nucleotide sequence of the cDNA encoding the variableregion of the 151D heavy chain is shown in SEQ ID NO: 14, and the aminoacid sequence thereof is shown in SEQ ID NO: 15.

6)-1-3 Amplification of cDNA Comprising 151D Light Chain Variable RegionAccording to 5′-RACE PCR, and Sequencing Thereof

Amplification and sequencing were carried out by the same method as thatapplied in Example 6)-1-2. However, as primers used to amplify the cDNAof the variable region of a 151D light chain gene according to PCR, UPM(Universal Primer A Mix: included with SMARTer RACE cDNA AmplificationKit) and primers designed from the sequences of the constant regions ofknown rat light chains were used.

The determined nucleotide sequence of the cDNA encoding the variableregion of the 151D light chain is shown in SEQ ID NO: 16, and the aminoacid sequence thereof is shown in SEQ ID NO: 17.

6)-2 Cloning and Sequencing of cDNA of Rat Antibody 198D

The sequences were determined by the same method as that applied inExample 6)-1.

The determined nucleotide sequence of the cDNA encoding the variableregion of the 198D heavy chain is shown in SEQ ID NO: 18, and the aminoacid sequence thereof is shown in SEQ ID NO: 19. The determinednucleotide sequence of the cDNA encoding the variable region of the 198Dlight chain is shown in SEQ ID NO: 20, and the amino acid sequencethereof is shown in SEQ ID NO: 21.

6)-3 Production of Human Chimeric Antibody Expression Vector

6)-3-1 Construction of Human Chimeric Light Chain Expression VectorpCMA-LK

An approx. 5.4-kb fragment, which had been obtained by digesting aplasmid pcDNA3.3-TOPO/LacZ (Invitrogen) with the restriction enzymesXbaI and PmeI, was bound to a DNA fragment comprising the human lightchain signal sequence shown in SEQ ID NO: 22 and a DNA sequence encodinga human κ chain constant region, using an In-Fusion Advantage PCRcloning kit (CLONTECH), to produce pcDNA3.3/LK.

A neomycin expression unit was removed from the pcDNA3.3/LK to constructpCMA-LK.

6)-3-2 Construction of Human Chimeric IgG1 Type Heavy Chain ExpressionVector pCMA-G1

A DNA fragment, which had been obtained by digesting pCMA-LK with XbaIand PmeI to remove the light chain signal sequence and the human κ chainconstant region therefrom, was bound to a DNA fragment comprising thehuman heavy chain signal sequence shown in SEQ ID NO: 23 and a DNAsequence encoding the amino acids in a human IgG1 constant region, usingan In-Fusion Advantage PCR cloning kit (CLONTECH), to construct pCMA-G1.

6)-3-3 Construction of Human Chimeric 151D Heavy Chain Expression Vector

Using, as a template, the cDNA encoding the variable region of a ratantibody 151D heavy chain obtained in Example

6)-1, PCR was carried out with primers designed for In-fusion cloning,so as to amplify a DNA fragment comprising cDNA encoding the heavy chainvariable region. Using an In-Fusion HD PCR cloning kit (Clontech), theamplified DNA fragment was inserted into a site of pCMA-G1 that had beencleaved with the restriction enzyme BIpI, so as to construct a humanchimeric 151D heavy chain expression vector.

The nucleotide sequence of the human chimeric 151D heavy chain and theamino acid sequence of this heavy chain are shown in SEQ ID NO: 24 andSEQ ID NO: 25, respectively.

6)-3-4 Construction of Human Chimeric 151D Light Chain Expression Vector

Using, as a template, the cDNA encoding the variable region of a 151Dlight chain variable region obtained in Example 6)-1, PCR was carriedout with primers designed for In-fusion cloning, so as to amplify a DNAfragment comprising cDNA encoding the light chain variable region. Usingan In-Fusion HD PCR cloning kit (Clontech), the amplified DNA fragmentwas inserted into a site of pCMA-LK that had been cleaved with therestriction enzyme BsiWI, so as to construct a human chimeric 151D lightchain expression vector.

The nucleotide sequence of the human chimeric 151D light chain and theamino acid sequence of this light chain are shown in SEQ ID NO: 26 andSEQ ID NO: 27, respectively.

6)-3-5 Construction of Human Chimeric 198D Heavy Chain Expression Vector

Using, as a template, the cDNA encoding the variable region of a ratantibody 198D heavy chain obtained in Example 6)-2, a human chimeric198D heavy chain expression vector was constructed by the same method asthat applied in Example 6)-3-3.

The nucleotide sequence of the human chimeric 198D heavy chain and theamino acid sequence of this heavy chain are shown in SEQ ID NO: 28 andSEQ ID NO: 29, respectively.

6)-3-6 Construction of Human Chimeric 198D Light Chain Expression Vector

Using, as a template, the cDNA encoding the variable region of a 198Dlight chain obtained in Example 6)-2, a human chimeric 198D light chainexpression vector was constructed by the same method as that applied inExample 6)-3-4.

The nucleotide sequence of the human chimeric 198D light chain and theamino acid sequence of this light chain are shown in SEQ ID NO: 30 andSEQ ID NO: 31, respectively.

6)-4 Preparation of Human Chimeric Antibody 6)-4-1 Production of HumanChimeric Antibody

In accordance with the manual, FreeStyle 293F cells (Invitrogen) werecultured and passaged. 1×10⁸ FreeStyle 293F cells (Invitrogen) in thelogarithmic growth phase were seeded on a 250-mL Fernbach ErlenmeyerFlask (CORNING), and were then diluted with FreeStyle293 expressionmedium (Invitrogen) at 2.0×10⁶ cells/mL.

Meanwhile, 20 μg of the heavy chain expression vector, 30 μg of thelight chain expression vector and 150 μg of Polyethyleneimine(Polyscience #24765) were added to 5 mL of Opti-Pro SFM medium(Invitrogen), and the obtained mixture was gently stirred. Afterincubation for 5 minutes, the mixture was added to the FreeStyle 293Fcells.

The cells were incubated in an incubator (37° C., 8% CO₂) with shakingat 125 rpm for 4 hours, and thereafter, 50 mL of EX-CELL VPRO medium(SAFC Biosciences), 0.36 mL of GlutaMAX I (GIBCO), and 2.5 mL ofYeastolate Ultrafiltrate (GIBCO) were added to the culture. The cellswere further incubated in an incubator (37° C., 8% CO₂) with shaking at125 rpm for 7 days. The culture supernatant was harvested and filtratedwith a 250-mL Filter System (CORNING, #431096).

A human chimeric 151D antibody obtained by the combination of the humanchimeric 151D heavy chain expression vector with the human chimeric 151Dlight chain expression vector was named “c151D,” whereas a humanchimeric 198D antibody obtained by the combination of the human chimeric198D heavy chain expression vector with the human chimeric 198D lightchain expression vector was named “c198D.”

6)-4-2 Purification of Chimeric Antibody

The culture supernatant obtained in Example 6)-4-1 was purified by aone-stage process of rProtein A affinity chromatography. The culturesupernatant was applied to a column (manufactured by GE HealthcareBioscience) that had been filled with MabSelectSuRe equilibrated withPBS, and the column was then washed with PBS in an amount of two or moretimes the volume of the column. Subsequently, elution was carried outusing a 2 M arginine hydrochloride solution (pH 4.0), so that a fractioncontaining an antibody was collected. This fraction was subjected toCentrifugal UF Filter Device VIVASPIN20 (molecular weight cutoff: UF30K,Sartorius), so that the buffer was replaced with PBS and the antibodywas concentrated, thereby adjusting the antibody concentration to 1mg/mL or more. Finally, the antibody was filtrated through Minisart-Plusfilter (Sartorius) to obtain a purified sample.

6)-5 Evaluation of Binding Activity of Human Chimeric Antibody to HumanGARP

The dissociation constant between the c151D or c198D produced in Example6)-4 and human GARP was evaluated by using Biacore T200 (GE HealthcareBioscience), according to a capture method, which comprises capturingthe antibody as a ligand with the immobilized Protein A and thenanalyzing the dissociation constant using an antigen (recombinant humanGARP: R&D Systems) as an analyte. HBS-EP+ (manufactured by GE HealthcareBioscience) was used as a running buffer, and a Protein A Sensor Chip(manufactured by GE Healthcare Bioscience) was used as a sensor chip.

The human chimeric antibody (1 μg/mL) was added onto the chip at a rateof 10 μL/min for 20 seconds, and a dilution series solution (8 to 128nM) of the antigen was then added at a flow rate of 30 μl/min for 120seconds. Subsequently, the dissociation was monitored for 480 seconds.As a regeneration solution, Glycine 1.5 (manufactured by GE HealthcareBioscience) was added at a flow rate of 20 μl/min for 30 seconds.

1:1 Fitting models were used in data analysis, and the association rateconstant ka, the dissociation rate constant kd, and the dissociationconstant (KD; KD=kd/ka) were calculated.

The results are shown in Table 1.

TABLE 1 Dissociation constant between c151D or c198D and human GARP NameKD (nM) 1 c151D 0.47 2 c198D 0.17

Example 7 Production of Humanized Antibody

7)-1 Molecular Modeling of c151D Antibody Variable Region

The molecular modeling of the variable region of the c151D antibody wascarried out according to a method that had been generally known ashomologous modeling (Methods in Enzymology, 203, 121-153, (1991)).

The primary sequence of the variable region of a human immunoglobulinregistered in Protein Data Bank (Nuc. Acid Res. 28, 235-242 (2000)) (athree-dimensional structure inferred from an X-ray crystal structure isavailable) was compared with the variable region of the c151D antibody.

The three-dimensional structure of the variable region was produced bycombining, with one another, the coordinates of the heavy chain andlight chain of the c151D antibody and a model having high sequencehomology to the interfaces, so as to obtain a “framework model.”

After that, the representative conformation of each CDR was incorporatedinto the framework model.

Finally, in order to eliminate atomic contact that was disadvantageousin terms of energy, an energy minimization calculation was carried out.The above described procedures were carried out using Discovery Studio(Dassault Systemes).

7)-2 Design of Amino Acid Sequence of Humanized 151D Antibody

A humanized 151D antibody was constructed according to a methodgenerally known as CDR grafting (Proc. Natl. Acad. Sci. USA 86,10029-10033 (1989)). An acceptor antibody was selected based on aminoacid homology in the framework region.

The sequence of the framework region of the c151D antibody was comparedwith the framework region of a human subgroup consensus sequencedetermined by KABAT et al. (Sequences of Proteins of ImmunologicalInterest, 5th Ed. Public Health Service National Institutes of Health,Bethesda, Md. (1991)). As a result, the consensus sequence of human γchain subgroup 3 and human κ chain subgroup 1 and 4 had high sequencehomology, and based on this, they were selected as acceptors.

With regard to the consensus sequence of human γ chain subgroup 3 andthe consensus sequences of human κ chain subgroup 1 and human κ chainsubgroup 4, the amino acid residues in the framework regions werealigned with the amino acid residues of the c151D antibody, so that thepositions, in which different amino acids were used, were identified.The positions of these residues were analyzed using thethree-dimensional model of the c151D antibody constructed in the above7)-1, and donor residues to be grafted onto the acceptor were selectedbased on the criteria given by Queen et al. (Proc. Natl. Acad. Sci. USA86, 10029-10033 (1989)).

The thus selected several donor residues were introduced into anacceptor antibody, so as to construct the sequence of humanized h151D asin the manner described in the following examples.

7)-3 Design of Humanized 151D Heavy Chain h151D-H7)-3-1 h151D-H1 Type Heavy Chain

A humanized 151D heavy chain designed by substituting the arginineresidue at amino acid position 35 with a glycine residue, the lysineresidue at amino acid position 37 with a leucine residue, the lysineresidue at amino acid position 38 with an arginine residue, the serineresidue at amino acid position 42 with an alanine residue, the threonineresidue at amino acid position 61 with a glycine residue, the glutamineresidue at amino acid position 62 with a lysine residue, the alanineresidue at amino acid position 68 with a serine residue, the arginineresidue at amino acid position 80 with an alanine residue, the alanineresidue at amino acid position 94 with a serine residue, the serineresidue at amino acid position 96 with an asparagine residue, theaspartic acid residue at amino acid position 103 with an asparagineresidue, the serine residue at amino acid position 107 with an alanineresidue, the threonine residue at amino acid position 112 with a valineresidue, the valine residue at amino acid position 130 with a threonineresidue, and the methionine residue at amino acid position 131 with aleucine residue in the c151D heavy chain shown in SEQ ID NO: 25 in thesequence listing, was named “h151D-H1 type heavy chain.”

In the nucleotide sequence (SEQ ID NO: 32) encoding the h151D-H1 typeheavy chain, the mature heavy chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 58 to 1398, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 58 to 408, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 409 to 1398. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 133 to 162 encoding CDRH1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 205 to 234 encoding CDRH2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 352 to 375 encoding CDRH3, in SEQ ID NO: 32 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 33) of the h151D-H1type heavy chain, the mature heavy chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 20 to 466, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 20 to 136, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 137 to 466. Theaforementioned variable region has CDRH1 consisting of the amino acidsequence at amino acid positions 45 to 54 in SEQ ID NO: 33 in thesequence listing, CDRH2 consisting of the amino acid sequence at aminoacid positions 69 to 78 therein, and CDRH3 consisting of the amino acidsequence at amino acid positions 118 to 125 therein.

Moreover, the sequences shown in SEQ ID NOS: 32 and 33 are also shown inFIGS. 31 and 21, respectively.

7)-3-2 h151D_H4 Type Heavy Chain

A humanized 151D heavy chain designed by substituting the arginineresidue at amino acid position 35 with a glycine residue, the lysineresidue at amino acid position 37 with a leucine residue, the lysineresidue at amino acid position 38 with an arginine residue, the serineresidue at amino acid position 42 with an alanine residue, the threonineresidue at amino acid position 61 with a glycine residue, the glutamineresidue at amino acid position 62 with a lysine residue, the alanineresidue at amino acid position 94 with a serine residue, the asparticacid residue at amino acid position 103 with an asparagine residue, theserine residue at amino acid position 107 with an alanine residue, thethreonine residue at amino acid position 112 with a valine residue, thevaline residue at amino acid position 130 with a threonine residue, andthe methionine residue at amino acid position 131 with a leucine residuein the c151D heavy chain shown in SEQ ID NO: 25 in the sequence listing,was named “h151D_H4 type heavy chain.”

In the nucleotide sequence (SEQ ID NO: 34) encoding the h151D-H4 typeheavy chain, the mature heavy chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 58 to 1398, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 58 to 408, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 409 to 1398. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 133 to 162 encoding CDRH1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 205 to 234 encoding CDRH2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 352 to 375 encoding CDRH3, in SEQ ID NO: 34 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 35) of the h151D-H4type heavy chain, the mature heavy chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 20 to 466, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 20 to 136, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 137 to 466. Theaforementioned variable region has CDRH1 consisting of the amino acidsequence at amino acid positions 45 to 54 in SEQ ID NO: 35 in thesequence listing, CDRH2 consisting of the amino acid sequence at aminoacid positions 69 to 78 therein, and CDRH3 consisting of the amino acidsequence at amino acid positions 118 to 125 therein.

Moreover, the sequences shown in SEQ ID NOS: 34 and 35 are also shown inFIGS. 33 and 23, respectively.

7)-4 Design of Humanized 151D Light Chain h151D_L7)-4-1 h151D-L1 Type Light Chain

A humanized 151D light chain designed by substituting the threonineresidue at amino acid position 29 with an aspartic acid residue, themethionine residue at amino acid position 31 with a leucine residue, thephenylalanine residue at amino acid position 32 with an alanine residue,the isoleucine residue at amino acid position 33 with a valine residue,the valine residue at amino acid position 35 with a leucine residue, theaspartic acid residue at amino acid position 37 with a glutamic acidresidue, the valine residue at amino acid position 39 with an alanineresidue, the methionine residue at amino acid position 41 with anisoleucine residue, the threonine residue at amino acid position 60 witha proline residue, the threonine residue at amino acid position 83 witha serine residue, the asparagine residue at amino acid position 97 witha serine residue, the methionine residue at amino acid position 98 witha leucine residue, the leucine residue at amino acid position 103 with avaline residue, the threonine residue at amino acid position 120 with aglutamine residue, the leucine residue at amino acid position 124 with avaline residue, the leucine residue at amino acid position 126 with anisoleucine residue, the asparagine residue at amino acid position 127with a lysine residue, and the alanine residue at amino acid position129 with a threonine residue in the c151D light chain shown in SEQ IDNO: 27 in the sequence listing, was named “h151D_L1 type light chain.”

In the nucleotide sequence (SEQ ID NO: 36) encoding the h151D-L1 typelight chain, the mature light chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 61 to 702, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 61 to 387, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 388 to 702. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 130 to 162 encoding CDRH1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 208 to 228 encoding CDRH2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 325 to 351 encoding CDRH3, in SEQ ID NO: 36 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 37) of the h151D_L1type light chain, the mature light chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 21 to 234, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 21 to 129, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 130 to 234. Theaforementioned variable region has CDRL1 consisting of the amino acidsequence at amino acid positions 44 to 54 in SEQ ID NO: 37 in thesequence listing, CDRL2 consisting of the amino acid sequence at aminoacid positions 70 to 76 therein, and CDRL3 consisting of the amino acidsequence at amino acid positions 109 to 117 therein.

Moreover, the sequences shown in SEQ ID NOS: 36 and 37 are also shown inFIGS. 32 and 22, respectively.

7)-4-2 h151D-L4 Type Light Chain:

A humanized 151D light chain designed by substituting the threonineresidue at amino acid position 29 with a serine residue, the methionineresidue at amino acid position 31 with a leucine residue, thephenylalanine residue at amino acid position 32 with a serine residue,the isoleucine residue at amino acid position 33 with an alanineresidue, the methionine residue at amino acid position 41 with anisoleucine residue, the threonine residue at amino acid position 60 witha proline residue, the glutamine residue at amino acid position 62 witha lysine residue, the threonine residue at amino acid position 83 with aserine residue, the asparagine residue at amino acid position 97 with aserine residue, the methionine residue at amino acid position 98 with aleucine residue, the alanine residue at amino acid position 100 with aproline residue, the leucine residue at amino acid position 103 with aphenylalanine residue, the valine residue at amino acid position 105with a threonine residue, the threonine residue at amino acid position120 with a glutamine residue, the leucine residue at amino acid position124 with a valine residue, the leucine residue at amino acid position126 with an isoleucine residue, the asparagine residue at amino acidposition 127 with a lysine residue, and the alanine residue at aminoacid position 129 with a threonine residue in the c151D light chainshown in SEQ ID NO: 27 in the sequence listing, was named “h151D-L4 typelight chain.”

In the nucleotide sequence (SEQ ID NO: 38) encoding the h151D-L4 typelight chain, the mature light chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 61 to 702, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 61 to 387, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 388 to 702. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 130 to 162 encoding CDRL1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 208 to 228 encoding CDRL2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 325 to 351 encoding CDRL3, in SEQ ID NO: 38 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 39) of the h151D_L4type light chain, the mature light chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 21 to 234, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 21 to 129, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 130 to 234. Theaforementioned variable region has CDRL1 consisting of the amino acidsequence at amino acid positions 44 to 54 in SEQ ID NO: 39 in thesequence listing, CDRL2 consisting of the amino acid sequence at aminoacid positions 70 to 76 therein, and CDRL3 consisting of the amino acidsequence at amino acid positions 109 to 117 therein.

Moreover, the sequences shown in SEQ ID NOS: 38 and 39 are also shown inFIGS. 34 and 24, respectively.

7)-5 Molecular Modeling of Variation Region of c198D

Molecular modeling of the variable region of the c198D antibody wascarried out according to a method generally known as homologous modeling(Methods in Enzymology, 203, 121-153, (1991)). The primary sequence ofthe variable region of a human immunoglobulin registered in Protein DataBank (Nuc. Acid Res. 28, 235-242 (2000)) (a three-dimensional structureinferred from an X-ray crystal structure is available) was compared withthe variable region of the c198D antibody.

The three-dimensional structure of the variable region was produced bycombining, with one another, the coordinates of the heavy chain andlight chain of the c198D antibody and a model having high sequencehomology to their interfaces, so as to obtain a “framework model.”

After that, the representative conformation of each CDR was incorporatedinto the framework model.

Finally, in order to eliminate atomic contact that was disadvantageousin terms of energy, an energy minimization calculation was carried out.The above described procedures were carried out using Discovery Studio(Dassault Systemes).

7)-6 Design of Amino Acid Sequence of Humanized 198D

A humanized 198D antibody was constructed according to a methodgenerally known as CDR grafting (Proc. Natl. Acad. Sci. USA 86,10029-10033 (1989)). An acceptor antibody was selected based on aminoacid homology in the framework region.

The sequence of the framework region of the c198D antibody was comparedwith the framework region of a human subgroup consensus sequencedetermined by KABAT et al. (Sequences of Proteins of ImmunologicalInterest, 5th Ed. Public Health Service National Institutes of Health,Bethesda, Md. (1991)). As a result, the consensus sequence of human γchain subgroup 2 and human κ chain subgroup 1 had high sequencehomology, and based on this, they ware selected as an acceptor. Inaddition, several residues in the consensus sequence of human γ chainsubgroup 3 were introduced into the acceptor of the heavy chain.

With regard to the consensus sequence of human γ chain subgroup 2comprising a portion of the consensus sequence of human γ chain subgroup3 and the consensus sequence of human κ chain subgroup 1, the amino acidresidues in the framework regions were aligned with the amino acidresidues of the c198D antibody, so that the positions, in whichdifferent amino acids were used, were identified. The positions of theseresidues were analyzed using a three-dimensional model of the c198Dantibody constructed in the above 7)-5, and donor residues to be graftedonto the acceptor were selected based on the criteria given by Queen etal. (Proc. Natl. Acad. Sci. USA 86, 10029-10033 (1989)).

The thus selected several donor residues were introduced into theacceptor antibody, so as to construct the sequence of humanized h198D asin the manner described in the following examples.

7)-7 Design of Humanized 198D Heavy Chain h198D-H7)-7-1 h198D-H3 Type Heavy Chain

A humanized 198D heavy chain designed by substituting the glutamineresidue at amino acid position 20 with a glutamic acid residue, thearginine residue at amino acid position 24 with a valine residue, theproline residue at amino acid position 28 with a glycine residue, theglutamine residue at amino acid position 32 with a lysine residue, theglutamic acid residue at amino acid position 61 with a glycine residue,the serine residue at amino acid position 80 with a proline residue, thealanine residue at amino acid position 81 with a serine residue, theleucine residue at amino acid position 86 with a valine residue, theserine residue at amino acid position 87 with a threonine residue, theserine residue at amino acid position 95 with an asparagine residue, thephenylalanine residue at amino acid position 98 with a serine residue,the methionine residue at amino acid position 101 with a leucineresidue, the threonine residue at amino acid position 103 with a serineresidue, the leucine residue at amino acid position 104 with a valineresidue, the glutamine residue at amino acid position 105 with athreonine residue, the threonine residue at amino acid position 106 withan alanine residue, the glutamic acid residue at amino acid position 107with an alanine residue, the methionine residue at amino acid position111 with a valine residue, the phenylalanine residue at amino acidposition 113 with a tyrosine residue, the alanine residue at amino acidposition 133 with a threonine residue, and the serine residue at aminoacid position 134 with a leucine residue in the c198D heavy chain shownin SEQ ID NO: 29 in the sequence listing, was named “h198D_H3 type heavychain.”

In the nucleotide sequence (SEQ ID NO: 40) encoding the h198D-H3 typeheavy chain, the mature heavy chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 58 to 1407, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 58 to 417, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 418 to 1407. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 130 to 162 encoding CDRH1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 205 to 231 encoding CDRH2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 349 to 384 encoding CDRH3, in SEQ ID NO: 40 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 41) of the h198D-H3type heavy chain, the mature heavy chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 20 to 469, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 20 to 139, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 140 to 469.Moreover, the sequences shown in SEQ ID NOS: 40 and 41 are also shown inFIGS. 35 and 25, respectively.

7)-8 Design of Humanized 198D Light Chain h198D-L7)-8-1 h198D-L4 Type Light Chain

A humanized 198D light chain designed by substituting the alanineresidue at amino acid position 29 with a serine residue, the glycineresidue at amino acid position 33 with an alanine residue, the leucineresidue at amino acid position 35 with a valine residue, the glutamicacid residue at amino acid position 37 with an aspartic acid residue,the threonine residue at amino acid position 38 with an arginineresidue, the glutamine residue at amino acid position 42 with athreonine residue, the glutamine residue at amino acid position 65 witha lysine residue, the glycine residue at amino acid position 85 with aserine residue, the serine residue at amino acid position 92 with athreonine residue, the lysine residue at amino acid position 94 with athreonine residue, the methionine residue at amino acid position 98 witha leucine residue, the threonine residue at amino acid position 100 witha proline residue, the glutamic acid residue at amino acid position 103with a phenylalanine residue, the glycine residue at amino acid position104 with an alanine residue, the valine residue at amino acid position105 with a threonine residue, the serine residue at amino acid position120 with a glutamine residue, the leucine residue at amino acid position124 with a valine residue, and the alanine residue at amino acidposition 129 with a threonine residue in the c198D light chain shown inSEQ ID NO: 31 in the sequence listing, was named “h198D-L4 type lightchain.”

In the nucleotide sequence (SEQ ID NO: 42) encoding the h198D-L4 typelight chain, the mature light chain, from which a signal sequence hasbeen removed, is encoded by the nucleotide sequence consisting of thenucleotides at nucleotide positions 61 to 702, the variable region isencoded by the nucleotide sequence consisting of the nucleotides atnucleotide positions 61 to 387, and the constant region is encoded bythe nucleotide sequence consisting of the nucleotides at nucleotidepositions 388 to 702. The aforementioned variable region has thenucleotide sequence consisting of the nucleotides at nucleotidepositions 130 to 162 encoding CDRL1, the nucleotide sequence consistingof the nucleotides at nucleotide positions 208 to 228 encoding CDRL2,and the nucleotide sequence consisting of the nucleotides at nucleotidepositions 325 to 351 encoding CDRL3, in SEQ ID NO: 42 in the sequencelisting.

In addition, in the amino acid sequence (SEQ ID NO: 43) of the h198D_L4type light chain, the mature light chain, from which a signal sequencehas been removed, is the amino acid sequence consisting of the aminoacids at amino acid positions 21 to 234, the variable region is theamino acid sequence consisting of the amino acids at amino acidpositions 21 to 129, and the constant region is the amino acid sequenceconsisting of the amino acids at amino acid positions 130 to 234.Moreover, the sequences shown in SEQ ID NOS: 42 and 43 are also shown inFIGS. 36 and 26, respectively.

7)-9 Construction of Expression Vector for Humanized Antibody

7)-9-1 Construction of Expression Vector for Humanized Anti-Human GARPAntibody h151D-H1L1

A DNA fragment comprising a sequence encoding the h151D-H1 type heavychain consisting of the nucleotides at nucleotide positions 58 to 1398of the nucleotide sequence of the h151D-H1 type heavy chain shown in SEQID NO: 32 in the sequence listing was synthesized (GENEART, artificialgene synthesis service). Using the synthesized DNA fragment, inaccordance with the protocols of Potelligent® CHOK1SV Technology byBioWa and Lonza, an expression vector for the h151D-H1 type heavy chainwas constructed. The constructed expression vector was named“GSV-h151D-H1.”

Subsequently, a DNA fragment comprising a sequence encoding the h151D-L1type light chain consisting of the nucleotides at nucleotide positions61 to 702 of the nucleotide sequence of the h151D-L1 type light chainshown in SEQ ID NO: 36 in the sequence listing was synthesized (GENEART,artificial gene synthesis service).

Using the synthesized DNA fragment, in accordance with the protocols ofPotelligent® CHOK1SV Technology by BioWa and Lonza, an expression vectorfor the h151D-L1 type light chain was constructed. The constructedexpression vector was named “GSV-h151D-L1.”

Subsequently, an MACA-1511a expression vector was constructed from thethus constructed expression vectors “GSV-h151D-H1” and “GSV-h151D-L1” inaccordance with the protocols of Potelligent® CHOK1SV Technology byBioWa and Lonza. The obtained expression vector was named“DGV-h151D-H1L1-GS.”

7)-9-2 Construction of Expression Vector for Humanized Anti-Human GARPAntibody h151D-H4L4

As in the case of Example 7)-9-1, a DNA fragment comprising a sequenceencoding the h151D-H4 type heavy chain consisting of the nucleotides atnucleotide positions 58 to 1398 of the nucleotide sequence of anh151D-H4 type heavy chain shown in SEQ ID NO: 34 in the sequencelisting, and a DNA fragment comprising a sequence encoding an h151D-L4type light chain consisting of the nucleotides at nucleotide positions61 to 702 of the nucleotide sequence of the h151D-L4 type light chainshown in SEQ ID NO: 38 in the sequence listing, were synthesized(GENEART, artificial gene synthesis service).

Using the synthesized DNA fragments, in accordance with the protocols ofPotelligent® CHOK1SV Technology by BioWa and Lonza, an MACA-1514aexpression vector was constructed. The obtained expression vector wasnamed “DGV-h151D-H4L4-GS.”

7)-9-3 Construction of Expression Vector for Humanized Anti-Human GARPAntibody h198D-H3L4

As in the case of Example 7)-9-1, a DNA fragment comprising a sequenceencoding the h198D-H3 type heavy chain consisting of the nucleotides atnucleotide positions 58 to 1407 of the nucleotide sequence of theh198D-H3 type heavy chain shown in SEQ ID NO: 40 in the sequencelisting, and a DNA fragment comprising a sequence encoding the h198D-L4type light chain consisting of the nucleotides at nucleotide positions61 to 702 of the nucleotide sequence of the h198D-L4 type light chainshown in SEQ ID NO: 42 in the sequence listing, were synthesized(GENEART, artificial gene synthesis service).

Using the synthesized DNA fragments, in accordance with the protocols ofPotelligent® CHOK1SV Technology by BioWa and Lonza, an MACA-1983aexpression vector was constructed. The obtained expression vector wasnamed “DGV-h198D-H3L4-GS.”

7)-10 Preparation of Humanized Anti-Human GARP Antibody

7)-10-1 Production of Cells that Produce Humanized Anti-Human GARPAntibody7)-10-1-1 Production of Cells that Produce Humanized Anti-Human GARPAntibody h151D-H1L1

Potelligent CHOK1SV cells (BioWa and Lonza) were transfected with thehumanized anti-human GARP antibody h151D-H1L1 expression vector,DGV-h151D-H1L1-GS, which had been constructed in Example 7)-9-1 inaccordance with the protocols of Potelligent® CHOK1SV Technology byBioWa and Lonza, so as to construct a cell line producing the humanizedanti-human GARP antibody h151D-H1L1. The obtained producing cell linewas named “MAC1-1.”

7)-10-1-2 Production of Cells that Produce Humanized Anti-Human GARPAntibody h151D-H4L4

As in the case of Example 7)-10-1-1, Potelligent CHOK1SV cells (BioWaand Lonza) were transfected with the humanized anti-human GARP antibodyh151D-H4L4 expression vector, DGV-h151D-H4L4-GS, which had beenconstructed in Example 7)-9-2, so as to construct a cell line producingthe humanized anti-human GARP antibody h151D-H4L4. The obtainedproducing cell line was named “MAC2-1.”

7)-10-1-3 Production of Cells that Produce Humanized Anti-Human GARPAntibody h198D-H3L4

As in the case of Example 7)-10-1-1, Potelligent CHOK1SV cells (BioWaand Lonza) were transfected with the humanized anti-human GARP antibodyh198D-H3L4 expression vector, DGV-h198D-H3L4-GS, which had beenconstructed in Example 7)-9-3, so as to construct a cell line producingthe humanized anti-human GARP antibody h198D-H3L4. The obtained cellline was named “MAC3-1.”

7)-10-2 Culture of Cells that Produce Humanized Anti-Human GARP Antibody7)-10-2-1 Culture of Cells that Produce Humanized Anti-Human GARPAntibody h151D-H1L1

The humanized anti-human GARP antibody h151D-H1L1-producing cell line“MAC1-1” produced in Example 7)-10-1-1 was cultured using a cultureapparatus Wave reactor (GE Healthcare Japan). The producing cell line“MAC1-1” was thawed in Dsp04B (JX Energy) medium, and was then culturedin Dsp04B (JX Energy) medium at 120 rpm in an incubator (37° C., 5%CO₂). The obtained culture solution was diluted with C36 (JX Energy)medium, and was then expansively cultured at 120 rpm in an incubator(37° C., 5% CO₂).

The obtained culture solution was diluted with the C36 medium at 30×10⁴cells/mL, and was then transferred into a WAVE CELLBAG (GE HealthcareBioscience), followed by performing a culture at 37° C. in 5% CO₂, at anair-supplying rate of 0.3 L/min, at a rotation rate of 18-24 rpm, at anangle of 6-8°, for 13 days.

From the 3rd day after initiation of the culture, FM4Ae2 medium(self-prepared) was added to the culture in an amount of 6% of theinitial culture volume per day. The obtained culture solution wasroughly filtrated through a depth filter Millistak MCOHC054H1 (MerckMillipore), and was then filtrated through a 0.22-μm filter (Sartorius)attached to Flexboy Bags. This filtrate was named “MACA-1511a culturesupernatant”.

7)-10-2-2 Culture of Cells that Produce Humanized Anti-Human GARPAntibody h151D-H4L4

In the same manner as that applied in Example 7)-10-2-1, the humanizedanti-human GARP antibody h151D-H4L4-producing cell line “MAC2-1”produced in Example 7)-10-1-2 was cultured and expanded, and thereafter,the cells were subjected to fed-batch culture using a culture apparatusWave reactor (GE Healthcare Japan). The obtained culture was dilutedwith C36 medium at 30×10⁴ cells/mL, and was then transferred into a WAVECELLBAG (GE Healthcare Bioscience), followed by performing a culture for13 days. The obtained culture solution was filtrated, and the obtainedfiltrate was named “MACA-1514a culture supernatant.”

7)-10-2-3 Culture of Cells that Produce Humanized Anti-Human GARPAntibody h198D-H3L4

In the same manner as that applied in Example 7)-10-2-1, the humanizedanti-human GARP antibody h198D-H3L4-producing cell line “MAC3-1”produced in Example 7)-10-1-3 was cultured and expanded, and thereafter,the cells were subjected to fed-batch culture using a culture apparatusWave reactor (GE Healthcare Japan). The obtained culture was dilutedwith C36 medium at 30×10⁴ cells/mL, and was then transferred into a WAVECELLBAG (GE Healthcare Bioscience), followed by performing a culture for13 days. The obtained culture solution was filtrated, and the obtainedfiltrate was named “MACA-1983a culture supernatant.”

7)-10-3 Purification of Humanized Anti-Human GARP Antibody

7)-10-3-1 Purification of Humanized Anti-Human GARP Antibody h151D-H1L1

The “MACA-1511a culture supernatant” obtained in Example 7)-10-2-1 waspurified by a three-step process, namely, by rProtein A affinitychromatography, anion exchange chromatography, and cation exchangechromatography.

First, the culture supernatant was applied to rProtein A affinitychromatographic resin that had been equilibrated with PBS. After theentire culture solution had entered the column, the column was washedwith PBS, a buffer containing arginine, and PBS. Subsequently, theremaining substance in the column was eluted with an acetate buffer, andan absorption peak at 280 nm was then collected. The collected solutionwas neutralized with a Tris buffer, and was then roughly filtratedthrough a glass fiber filter AP20 (Merck Millipore). The solution wasfiltrated through Stericup-GV (Merck Millipore) that was a 0.22-μmfilter, and the resultant filtrate was defined as an rProtein A purifiedpool.

Subsequently, the rProtein A purified pool was applied to an anionexchange chromatographic resin that had been equilibrated with PBS.After the applied solution as a whole had entered the column, PBS wassupplied. A flow-through fraction and the absorption peak at 280 nm atthe time of the supply of PBS were collected. The pH of the collectedsolution was adjusted with acetic acid, and the solution was thenroughly filtrated through a glass fiber filter AP20 (Merck Millipore).The solution was filtrated through Stericup-GV (Merck Millipore) thatwas a 0.22-μm filter, and the resultant filtrate was defined as an AEXpurified pool.

Subsequently, the AEX purified pool was applied to a cation exchangechromatographic resin that had been equilibrated with an acetate buffer.After the applied solution as a whole had entered the column, the columnwas washed with an acetate buffer. Thereafter, elution was carried outusing an acetate buffer containing a high concentration of NaCl, and theabsorption peak at 280 nm was collected. The collected solution wasroughly filtrated through a glass fiber filter AP20 (Merck Millipore),and was then filtrated through Stericup-GV (Merck Millipore) that was a0.22-μm filter. The resultant filtrate was defined as a CEX purifiedpool.

The CEX purified pool was concentrated to an antibody concentration of25 mg/mL with Pellicon 3 Cassette 30 kDa (Merck Millipore), and thebuffer was then replaced with a histidine buffer (25 mM Histidine, 5%Sorbitol, pH 6.0). Finally, the solution was roughly filtrated through aglass fiber filter AP20 (Merck Millipore), and was then filtratedthrough Stericup-GV (Merck Millipore) that was a 0.22-μm filter, so asto obtain a purified sample. This purified sample was named“h151D-H1L1.”

7)-10-3-2 Purification of Humanized Anti-Human GARP Antibody h151D-H4L4

In the same manner as that applied in Example 7)-10-3-1, the “MACA-1514aculture supernatant” obtained in Example 7)-10-2-2 was purified by athree-stage process, namely, by rProtein A affinity chromatography,anion exchange chromatography, and cation exchange chromatography. Thepurified sample was named “h151D-H4L4.”

7)-10-3-3 Purification of Humanized Anti-Human GARP Antibody h198D-H3L4

In the same manner as that applied in Example 7)-10-3-1, the “MACA-1983aculture supernatant” obtained in Example 7)-10-2-3 was purified by athree-stage process, namely, by rProtein A affinity chromatography,anion exchange chromatography, and cation exchange chromatography. Thepurified sample was named “h198D-H3L4.”

7)-11 Evaluation of Binding Activity of Humanized Anti-Human GARPAntibodies to Human GARP

The dissociation constant between each of the humanized anti-human GARPantibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4 produced in Example7)-10 and GARP was evaluated by using Biacore T200 (GE HealthcareBioscience), according to a capture method, which comprises capturingthe antibody as a ligand by the immobilized Protein A and then analyzingthe dissociation constant using an antigen as an analyte.HBS-EP+(manufactured by GE Healthcare Bioscience) was used as a runningbuffer, and a Protein A Sensor Chip (manufactured by GE HealthcareBioscience) was used as a sensor chip.

The human chimeric antibody (1 μg/mL) was added onto the chip at a rateof 10 μL/min for 20 seconds, and a dilution series solution (8 to 128nM) of the antigen was added at a flow rate of 30 μl/min for 120seconds. Subsequently, the dissociation was monitored for 480 seconds.As a regeneration solution, Glycine 1.5 (manufactured by GE HealthcareBioscience) was added at a flow rate of 20 μl/min for 30 seconds.

1:1 Fitting model was used in data analysis, and the association rateconstant ka, the dissociation rate constant kd, and the dissociationconstant (KD; KD=kd/ka) were calculated.

The results are shown in Table 2.

TABLE 2 Dissociation constant of humanized anti-human GARP antibodiesName KD (nM) 1 h151D-H1L1 1.8 2 h151D-H4L4 1.2 3 h198D-H3L4 0.088

Example 8: Binding to Antigen Gene-Expressing Cells 8)-1 Binding to GARP

According to the method described in Example 2, an HEK-293T cellsuspension, into which a human GARP expression vector or a controlvector had been transfected, was prepared. h151D-H1L1, h151D-H4L4,h198D-H3L4, and control human IgG (human IgG: Eureka Therapeutics) wereadded to the cell suspension, and the cells were incubated at 4° C. for15 minutes.

The cells were washed twice with FACS buffer (PBS (Invitrogen)supplemented with 3% FBS), and thereafter, R-Phycoerythrin (PE)-labeledanti-IgG antibody (Jackson ImmunoResearch Laboratories) and HorizonFVS450 (Becton Dickinson) were added and suspended. The cells werefurther incubated at 4° C. for 15 minutes. The flow cytometric analysiswas carried out as described in Example 2, and a histogram of PEfluorescence intensity was generated (FIG. 37).

The histograms of fluorescence intensity for h151D-H1L1, h151D-H4L4, andhI98D-H3L4 in HEK-293T cells transfected with control vector weresimilar to the histogram for control IgG (in the figure, the cells arereferred to as “Mock vector-transfected HEK-293T”).

On the other hand, it was confirmed that the histograms of fluorescenceintensity for h151D-H1L1, h151D-H4L4 and h198D_H3L4 shifted to thestrong fluorescence intensity side in HEK-293T cells expressing GARP(which are referred to as “hGARP-transfected HEK-293T” in the figure) incomparison to the histogram for control human IgG.

From the aforementioned results, it was found that h151D-H1L1,h151D-H4L4 and h198D-H3L4 specifically bound to GARP.

8)-2 Binding to GARP-TGF β1 8)-2-1 Construction of Human GARP MutantExpression Vector

Using a human GARP expression vector (Origene) as a template, and alsousing primer F (cacggcaacctgctggagcggctgctgggggagg) (SEQ ID NO: 44),primer R (caggctgttcccagacaggtccag) (SEQ ID NO: 45), andKOD-Plus-Mutagenesis Kit (Toyobo), YSG at amino acid positions 137-139in the human GARP amino acid sequence (SEQ ID NO: 1) was converted toHGN, so as to construct a human GARP mutant expression vector. Then, thenucleotide sequence of this vector was confirmed.

8)-2-2 Co-Expression of GARP-TGF β1

Using Lipofectamine 2000 (Invitrogen), HEK-293T cells were transfectedwith a human TGF β1 expression vector (Sino Biological), as well as ahuman GARP expression vector or a human GARP mutant expression vector.

The cells were cultured in DMEM medium (Invitrogen) supplemented with10% FBS overnight in 5% CO₂ at 37° C., and the cells were then harvestedfrom the plate by treating them with TrypLE Express (Invitrogen). Theharvested cells were washed twice with FACS buffer and were re-suspendedin the same solution.

The antibodies 105F, h151D-H1L1, h151D-H4L4 and h198D-H3L4 in thepresent invention, known antibodies (human IgG1 anti-GARP antibodiesMHG8 and LHG10 which were produced based on the sequence informationdescribed in Patent Literature 1), and control human IgG (EurekaTherapeutics) were added to the cell suspension, and the cells wereincubated at 4° C. for 15 minutes.

The cells were washed twice with FACS buffer, and PE-labeled anti-IgGantibody (Jackson ImmunoResearch Laboratories) and Horizon FVS450(Becton Dickinson) were added and suspended. The cells were furtherincubated at 4° C. for 15 minutes. The flow cytometric analysis wascarried out as described in Example 2, and histograms of PE fluorescenceintensity were generated (FIG. 38).

It was confirmed that the histograms for all of the antibodies shiftedto the strong fluorescence intensity side in HEK-293T cellsco-transfected with TGF β1 and GARP in comparison to the histograms forthe control IgG (FIG. 38).

On the other hand, the histograms for MHG8 and LHG10 did not shift andwere similar to the histograms for the control IgG in HEK-293T cellsco-transfected with TGF β1 and a GARP mutant, whereas the histograms forthe antibodies 105F, h151D-H1L1, h151D-H4L4 and h198D-H3L4 shifted tothe strong fluorescence intensity side in the cells. Thus, it wasdemonstrated that the antibodies MHG8 and LHG10 did not bind to the GARPmutant, as described in [Non Patent Literature 12].

From the aforementioned results, it was demonstrated that the antibodies105F, h151D-H1L1, h151D-H4L4 and h198D-H3L4 bound to both GARP and theGARP mutant on cells co-expressing TGF β1, and it was found that theseantibodies bound to regions different from those to which the MHG8 andLHG10 antibodies bound.

Example 9: Binding to Endogenous GARP-Expressing Cells 9)-1 FlowCytometric Analysis Using L428 Cells

L428 cells were washed twice with FACS buffer and suspended in the samesolution. Thereafter, h151D-H1L1, h151D-H4L4, h198D_H3L4, and controlhuman IgG (human IgG: Eureka Therapeutics) were added to the suspension,and the cells were incubated at 4° C. for 15 minutes. The cells werewashed twice with FACS buffer, and PE-labeled anti-IgG antibody (JacksonImmunoResearch Laboratories) was added and suspended. The cells wereincubated at 4° C. for 15 minutes. Flow cytometric analysis was carriedout as described in Example 3, and histograms of PE fluorescenceintensity were generated.

As a result, the histograms for the antibodies h151D-H1L1, h151D-H4L4and h198D_H3L4 shifted to the strong fluorescence intensity side in L428cells in comparison to the histograms for the control IgG. Thus, it wasconfirmed that h151D-H1L1, h151D-H4L4 and h198D-H3L4 bound toendogenously expressed GARP (FIG. 39).

9)-2 Flow Cytometric Analysis Using Human Treg

Frozen human PBMC (Cellular Technology) was thawed in accordance withthe protocols, and the PBMC was seeded at 2×10⁶ cells/mL in a 24-wellplate (Sumitomo Bakelite Co., Ltd.) using RPMI1640 medium (Invitrogen)supplemented with 10% FBS.

Dynabeads Human T-Activator CD3/CD28 (Life technologies) was added tothe plate, and the cells were cultured for 48 hours. Thereafter, thecells were suspended in FACS buffer, and the antibodies h151D-H1L1,h151D-H4L4 and h198D-H3L4, and control human IgG (human IgG: EurekaTherapeutics) were added. APC-labeled anti-CD4 antibody (BectonDickinson) was also added to the suspension. The cells were incubated at4° C. for 10 minutes.

The cells were washed with FACS buffer, and thereafter, FITC-labeledanti-IgG antibody (Jackson ImmunoResearch Laboratories) and HorizonFVS450 (Becton Dickinson) were added and suspended. The cells werefurther incubated at 4° C. for 15 minutes.

The cells were washed with FACS buffer again and re-suspended insolution using FoxP3 Staining Buffer Set (Miltenyi Biotec). After that,PE-labeled anti-Foxp3 antibody (Miltenyi Biotec) was added to the cells,and the cells were incubated at 4° C. for 30 minutes.

After the cells were washed, the cells were measured using a flowcytometer (FACS Canto II; Becton Dickinson). CD4-positive cells wereanalyzed using FlowJo (Tree Star) after dead cells were removed from theanalysis by gating out cells stained with Horizon FVS450.

The results demonstrated that the antibodies h151D-H1L1, h151D-H4L4 andh198D-H3L4 bound to FoxP3-positive Treg (FIG. 40).

Example 10: Properties of Anti-GARP Antibody 10)-1 ADCC Activity

The antibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4, known antibodies(human IgG1 anti-GARP antibodies MHG8 and LHG10 produced based on thesequence information described in Patent Literature 1), and controlhuman IgG (Sigma) were analyzed for their ADCC activity according to themethod described in Example 4.

The antibodies h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibited cytolyticactivity on L428 cells in an antibody concentration-dependent manner(FIG. 41A).

In contrast, as described in Example 4, MHG8 and LHG10 did not exhibitsuch cytolytic activity in the same way that the control human IgG didnot (FIG. 41B).

From the aforementioned results, it was demonstrated that the antibodiesh151D-H1L1, h151D-H4L4 and h198D-H3L4 had ADCC activity.

10)-2 Inhibitory Activity to Treg Function

The antibodies h151D-H1L1, h151D-H4L4, and h198D-H3L4 were analyzed fortheir inhibitory activity to Treg function according to the methoddescribed in Example 4. The inhibitory activity of h151D-H1L1,h151D-H4L4, and h198D-H3L4 to Treg function at a final concentration of1 μg/mL is shown in FIG. 42 (inhibitory rate of h151D-H1L1: 81.5%;inhibitory rate of h151D-H4L4: 80.4%; and inhibitory rate of h198D-H3L4:70.8%).

It was demonstrated that the antibodies h151D-H1L1, h151D-H4L4, andh198D-H3L4 had inhibitory activity to Treg function.

10)-3 Antitumor Activity (In Vitro) 10)-3-1 Preparation of Cytotoxic TLymphocytes (CTL)

According to the protocol from Mie University, CTL cells having anNY-ESO-1-specific T cell receptor (MU28 CD8B35 Clone #7: obtained fromMie University) were incubated at 3×10⁵ cells in a 25 cm² flask(Sumitomo Bakelite Co., Ltd.) in the presence of an anti-CD3 antibody(OKT3: Imgenex), IL-2 (Novartis), and feeder cells in RPMI1640 medium(Invitrogen) supplemented with 10% Human male AB serum (Sigma) for 7days.

With regard to the feeder cells, frozen human PBMC (Cellular Technology)was thawed and CD8-positive cells were removed from the PBMC using CD8MicroBeads (Miltenyi Biotech) to obtain CD8-depleted PBMC (7.5×10⁶cells/25 cm² flask) and the cells were X-ray irradiated. In addition,103-LCL cells (obtained from Riken BioResource Center) (1.5×10⁶ cells/25cm² flask) were also X-ray irradiated by using an X-ray irradiator(Hitachi Medical Corporation). These cells were used as feeder cells.

Treg obtained by the method described in Example 4)-2-1 were added uponinitiation of culture (1.5×10⁵ cells/25 cm² flask) in order to evaluatethe suppressive effect of Treg on CTL cell activity. In addition, Treg(7.5×10⁴ cells/25 cm² flask) obtained by the aforementioned method andthe antibodies 105F, h151D-H1L1, h151D-H4L4, h198D-H3L4 and human IgG1(Enzo) were added upon initiation of culture (10 μg/ml) in order toevaluate the antitumor activity of each antibody.

After completion of the culture, CD8-positive cells were purified andseparated to prepare CTL cells using a CD8⁺ T Cell Isolation Kit(Miltenyi Biotech). Thereafter, the prepared CTL cells were used in theevaluation of activity.

10)-3-2 Preparation of Target Cells

A human melanoma cell line, namely, NY-ESO-1-expressing SK-MEL-52 cells(obtained from Mie University: Proc Natl Acad Sci USA. 1980 July; 77(7):4260-4) were cultured using RPMI1640 medium (Invitrogen) supplementedwith 10% FBS. The labeling of the cells with ⁵¹Cr was carried out asdescribed in Example 4)-1-2, and the cells were adjusted to 2×10⁴cells/mL. The obtained cells were defined as target cells.

10)-3-3 ⁵¹Cr Release Assay

The target cells were dispensed in a 96-well U-bottom microplate(Costar) (50 μL/well).

Subsequently, CTL cells were added to the plate (100 μL/well), so thatthe number of CTL cells would be 16, 8, 4, or 2 times more than thenumber of target cells (CTL cells target cells=16:1, 8:1, 4:1, or 2:1),and the cells were incubated in 5% CO₂ at 37° C. for 4 hours. Afterthat, the cells were processed according to the method as described inExample 4)-1-3. It is to be noted that the inhibitory activity of asample is calculated every time in each experiment. In addition, it wasconfirmed that the CTL cells do not exhibit cytolytic activity to cellsthat do not express NY-ESO-1.

The measurement results are shown in FIGS. 43 and 44.

The cytolytic activity of the CTL cells to SK-MEL-52 was suppressed byTreg (FIG. 43).

On the other hand, the cell lysis rates of CTL cells against SK-MEL-52cells elevated as the number of the CTL cells increased in the CTL cellsto which the antibodies 105F, h151D-H1L1, h151D-H4L4, or h198D-H3L4 hadbeen added, and also, the cell lysis rates were clearly higher than thatof the control CTL cells to which the control IgG had been added (FIG.44) at any target-effector ratio.

Therefore, it was demonstrated that the antibodies 105F, h151D-H1L1,h151D-H4L4 and h198D-H3L4 inhibited the suppressive activity of Treg toCTL cells, and enhanced antitumor activity.

10)-4 Antitumor Activity (In Vivo)

It is known that the antitumor effects of a chimeric antibody havingADCC activity can be evaluated in NOD/Shi-scid, IL-2R^(null) (NOG) miceinto which L428 cells had been transplanted and human PBMC areadministered (J Immunol. 2009 Oct. 1; 183(7): 4782-91).

L428 cells (DSMZ), which had been suspended in a mixed solution ofRPMI1640 medium (Invitrogen) and Matrigel (Becton Dickinson) (1:1) at1×10⁷ cells/mL, were transplanted in an volume of 0.1 mL into thesubcutis of the axillary region of NOG mice (female, In vivo science).The day at which the L428 cells were transplanted was defined as Day 0.On Day 6, the mice were divided into groups based on the tumor volumevalue (n=6 in each group), and the groups of administration were set asfollows.

PBS control 1: administered on Days 6, 10, 14, 18, 22 and 26, and also,human PBMC (Lot: 20140707) was administered on Days 6, 14 and 22

105F antibody: administered at a dose of 5 mg/kg on Days 6, 10, 14, 18,22 and 26, and also, human PBMC (Lot: 20140707) was administered on Days6, 14 and 22

PBS control 2: administered on Days 6, 10, 14, 18, 22, and also, humanPBMC (Lot: 20150924) was administered on Days 6, 14 and 22

h151D-H1L1 antibody: administered at a dose of 1 mg/kg on Days 6, 10,14, 18 and 22, and also, human PBMC (Lot: 20150924) was administered onDays 6, 14 and 22

h151D-H4L4 antibody: administered at a dose of 1 mg/kg on Days 0, 6, 10,14, 18 and 22, and also, human PBMC (Lot: 20150924) was administered onDays 6, 14 and 22

h198D-H3L4 antibody: administered at a dose of 1 mg/kg on Days 0, 6, 10,14, 18 and 22, and also, human PBMC (Lot: 20150924) was administered onDays 6, 14 and 22

Each antibody was diluted with PBS (Invitrogen) and administered to themice through the tail vein (10 mL/kg).

Regarding human PBMC, frozen human PBMC (Cellular Technology) was thawedin accordance with the protocols and prepared at 1×10⁷ cells/mL. Theprepared cells (0.2 mL) were administered to the mice through the tailvein.

The long diameter (mm) and short diameter (mm) of tumor were measuredover time, using electronic digital calipers (Mitutoyo), and the volumeof the tumor was then calculated according to the following expression.

Tumor volume (mm3)=½×[long diameter of tumor]×[short diameter oftumor]×[short diameter of tumor]

A change in the mean value±standard error (SE) of the tumor volume ineach group is shown in FIG. 45.

The antibodies 105F, h151D-H1L1, h151D-H4L4 and h198D-H3L4 exhibitedantitumor activity to the L428 cells, in comparison to the control groupto which only PBMC was administered. Thus, a significant difference wasobserved with respect to the control group (105F: t-test; andh151D-H1L1, h151D-H4L4 and h198D-H3L4: Dunnett's multiple comparisontest). The results of the significant difference test (P values) on thefinal measurement day of individual groups (105F: Day 31; andh151D-H1L1, h151D-H4L4 and h198D-H3L4: Day 25) are also shown in thefigure.

Therefore, the antibodies 105F, h151D-H1L1, h151D-H4L4 and h198D-H3L4exhibited antitumor activity in in vivo models.

Example 11: Epitope Analysis of Anti-GARP Antibody

The epitopes of anti-human GARP antibodies (105F, 110F, h151D-H1L1, andh198D-H3L4) were analyzed by hydrogen-deuterium exchange massspectrometry.

A 7 mg/mL anti-human GARP antibody was mixed with 3 mg/mL human GARP(R&D Systems) or a blank buffer in equal amounts. To the obtainedsolution, 9 equivalents of light water or heavy water was added. After30 seconds, 480 seconds, or 6000 seconds of the addition of the water,or after one night had passed, 100 mM phosphoric acid, 4 M Gdn-HCl and150 mM TCEP (pH 2.5) were added in equal amounts to the sample, so thatthe obtained mixture was then subjected to deuterium substitution. Thethus deuterium-substituted sample was injected into HPLC under cooling,and it was then supplied to an immobilized pepsin column with a 0.1% TFAsolution.

A peptide fragment obtained by digestion of human GARP in the pepsincolumn was retained in a C18 trap column, was then eluted by lineargradient of water and acetonitrile to which 0.1% formic acid and 0.025%TFA had been added, and was then separated in a C18 analysis column. Theseparated peptide fragment was subjected to mass spectrometry using atime-of-flight mass spectrometer.

The deuterium substitution rate was calculated from the mass of eachpeptide. A peptide fragment, in which a significant reduction in thedeuterium substitution rate was observed as a result of addition of theanti-human GARP antibody, was identified to be an epitope fragment.

In the case of 105F, suppression of the deuterium substitution rate wasfound in the amino acid residues at positions 366-377, 407-445, and456-470 of the human GARP shown in SEQ ID NO: 1, and thus, they wereidentified to be an epitope.

In the case of 110F, suppression of the deuterium substitution rate wasfound in the amino acid residues at positions 54-112 and 366-392 of thehuman GARP shown in SEQ ID NO: 1, and thus, they were identified to bean epitope.

In the case of h151D-H1L1, suppression of the deuterium substitutionrate was found in the amino acid residues at positions 352-392 of thehuman GARP shown in SEQ ID NO: 1, and thus, they were identified to bean epitope.

In the case of h198D-H3L4, suppression of the deuterium substitutionrate was found in the amino acid residues at positions 18-112 of thehuman GARP shown in SEQ ID NO: 1, and thus, they were identified to bean epitope.

INDUSTRIAL APPLICABILITY

The anti-GARP antibody of the present invention has an antitumoractivity caused by inhibitory activity to Treg function, which ismediated by an ADCC activity, and thus, a pharmaceutical compositioncomprising the anti-GARP antibody can be used as an anticancer agent.

Moreover, the excessive presence of Treg and the activation thereof inpatients having malaria and HIV infection exhibit a correlation with thedisease state, and the removal of Treg induces remission of each diseasein murine models for the diseases. Accordingly, it can be expected thateffective inhibition of Treg function will also have therapeutic effectson refractory infections such as malaria and HIV.

Sequence Listing Free Text

SEQ ID NO: 1—Amino acid sequence of GARPSEQ ID NO: 2—Amino acid sequence of 105F antibody heavy chainSEQ ID NO: 3—Amino acid sequence of 105F antibody light chainSEQ ID NO: 4—Amino acid sequence of 110F antibody heavy chainSEQ ID NO: 5—Amino acid sequence of 110F antibody light chainSEQ ID NO: 6—Nucleotide sequence of 105F antibody heavy chainSEQ ID NO: 7—Nucleotide sequence of 105F antibody light chainSEQ ID NO: 8—Nucleotide sequence of 110F antibody heavy chainSEQ ID NO: 9—Nucleotide sequence of 110F antibody light chain

SEQ ID NO: 10—Primer A SEQ ID NO: 11—Primer B SEQ ID NO: 12—Primer C SEQID NO: 13—Primer D

SEQ ID NO: 14—Nucleotide sequence of cDNA encoding variable region of151D heavy chainSEQ ID NO: 15—Amino acid sequence of variable region of 151D heavy chainSEQ ID NO: 16—Nucleotide sequence of cDNA encoding variable region of151D light chainSEQ ID NO: 17—Amino acid sequence of variable region of 151D light chainSEQ ID NO: 18—Nucleotide sequence of cDNA encoding variable region of198D heavy chainSEQ ID NO: 19—Amino acid sequence of variable region of 198D heavy chainSEQ ID NO: 20—Nucleotide sequence of cDNA encoding variable region of198D light chainSEQ ID NO: 21—Amino acid sequence of variable region of 198D light chainSEQ ID NO: 22—Nucleotide sequence of DNA fragment comprising human lightchain signal sequence and sequence encoding amino acids in human κ chainconstant regionSEQ ID NO: 23—Nucleotide sequence of DNA fragment comprising human heavychain signal sequence and sequence encoding amino acids in human IgG1constant regionSEQ ID NO: 24—Nucleotide sequence of human chimeric antibody c151D heavychainSEQ ID NO: 25—Amino acid sequence of human chimeric antibody c151D heavychainSEQ ID NO: 26—Nucleotide sequence of human chimeric antibody c151D lightchainSEQ ID NO: 27—Amino acid sequence of human chimeric antibody c151D lightchainSEQ ID NO: 28—Nucleotide sequence of human chimeric antibody c198D heavychainSEQ ID NO: 29—Amino acid sequence of human chimeric antibody c198D heavychainSEQ ID NO: 30—Nucleotide sequence of human chimeric antibody c198D lightchainSEQ ID NO: 31—Amino acid sequence of human chimeric antibody c198D lightchainSEQ ID NO: 32—Nucleotide sequence of humanized antibody h151D-H1SEQ ID NO: 33—Amino acid sequence of humanized antibody h151D-H1SEQ ID NO: 34—Nucleotide sequence of humanized antibody h151D-H4SEQ ID NO: 35—Amino acid sequence of humanized antibody h151D-H4SEQ ID NO: 36—Nucleotide sequence of humanized antibody h151D-L1SEQ ID NO: 37—Amino acid sequence of humanized antibody h151D-L1SEQ ID NO: 38—Nucleotide sequence of humanized antibody h151D-L4SEQ ID NO: 39—Amino acid sequence of humanized antibody h151D-L4SEQ ID NO: 40—Nucleotide sequence of humanized antibody h198D-H3SEQ ID NO: 41—Amino acid sequence of humanized antibody h198D-H3SEQ ID NO: 42—Nucleotide sequence of humanized antibody h198D-L4SEQ ID NO: 43—Amino acid sequence of humanized antibody h198D-L4

SEQ ID NO: 44—Primer F SEQ ID NO: 45—Primer R

1. An antibody having the following properties: (1) specifically bindingto Glycoprotein-A Repetitions Predominant (GARP); (2) having aninhibitory activity to the immunosuppressive function of regulatory Tcells; (3) having antibody-dependent cellular cytotoxic (ADCC) activity;and (4) having in vivo antitumor activity.
 2. The antibody according toclaim 1, wherein the GARP is a molecule consisting of the amino acidsequence shown in SEQ ID NO:
 1. 3. The antibody according to claim 1,which binds to: (1) an amino acid sequence portion at amino acidpositions 366 to 377, 407 to 445 and 456 to 470 shown in SEQ ID NO: 1,(2) an amino acid sequence portion at amino acid positions 54 to 112 and366 to 392 shown in SEQ ID NO: 1, (3) an amino acid sequence portion atamino acid positions 352 to 392 shown in SEQ ID NO: 1, or (4) an aminoacid sequence portion at amino acid positions 18 to 112 shown in SEQ IDNO:
 1. 4. The antibody according to claim 1, which has competitiveinhibitory activity, for binding to GARP, against an antibody having:(1) a heavy chain consisting of the amino acid sequence shown in SEQ IDNO: 2 and a light chain consisting of the amino acid sequence shown inSEQ ID NO: 3, (2) a heavy chain consisting of the amino acid sequenceshown in SEQ ID NO: 4 and a light chain consisting of the amino acidsequence shown in SEQ ID NO: 5, (3) a heavy chain consisting of theamino acid sequence shown in SEQ ID NO: 25 and a light chain consistingof the amino acid sequence shown in SEQ ID NO: 27, or (4) a heavy chainconsisting of the amino acid sequence shown in SEQ ID NO: 29 and a lightchain consisting of the amino acid sequence shown in SEQ ID NO:
 31. 5.The antibody according to claim 1, wherein the tumor is a cancer.
 6. Theantibody according to claim 5, wherein the cancer is lung cancer, kidneycancer, urothelial cancer, colon cancer, prostate cancer, glioblastomamultiforme, ovarian cancer, pancreatic cancer, breast cancer, melanoma,liver cancer, bladder cancer, stomach cancer, esophageal cancer, orblood cancer.
 7. The antibody according to claim 1, which has: (1) CDRH1consisting of the amino acid sequence at amino acid positions 26 to 35shown in SEQ ID NO: 2, CDRH2 consisting of the amino acid sequence atamino acid positions 50 to 66 shown in SEQ ID NO: 2 and CDRH3 consistingof the amino acid sequence at amino acid positions 99 to 107 shown inSEQ ID NO: 2, and CDRL1 consisting of the amino acid sequence at aminoacid positions 23 to 36 shown in SEQ ID NO: 3, CDRL2 consisting of theamino acid sequence at amino acid positions 52 to 58 shown in SEQ ID NO:3 and CDRL3 consisting of the amino acid sequence at amino acidpositions 91 to 101 shown in SEQ ID NO: 3, (2) CDRH1 consisting of theamino acid sequence at amino acid positions 26 to 35 shown in SEQ ID NO:4, CDRH2 consisting of the amino acid sequence at amino acid positions50 to 66 shown in SEQ ID NO: 4 and CDRH3 consisting of the amino acidsequence at amino acid positions 99 to 112 shown in SEQ ID NO: 4, andCDRL1 consisting of the amino acid sequence at amino acid positions 23to 36 shown in SEQ ID NO: 5, CDRL2 consisting of the amino acid sequenceat amino acid positions 52 to 58 shown in SEQ ID NO: 5 and CDRL3consisting of the amino acid sequence at amino acid positions 91 to 100shown in SEQ ID NO: 5, (3) CDRH1 consisting of the amino acid sequenceat amino acid positions 45 to 54 shown in SEQ ID NO: 25, CDRH2consisting of the amino acid sequence at amino acid positions 69 to 78shown in SEQ ID NO: 25 and CDRH3 consisting of the amino acid sequenceat amino acid positions 118 to 125 shown in SEQ ID NO: 25, and CDRL1consisting of the amino acid sequence at amino acid positions 44 to 54shown in SEQ ID NO: 27, CDRL2 consisting of the amino acid sequence atamino acid positions 70 to 76 shown in SEQ ID NO: 27 and CDRL3consisting of the amino acid sequence at amino acid positions 109 to 117shown in SEQ ID NO: 27, or (4) CDRH1 consisting of the amino acidsequence at amino acid positions 45 to 54 shown in SEQ ID NO: 29, CDRH2consisting of the amino acid sequence at amino acid positions 69 to 77shown in SEQ ID NO: 29 and CDRH3 consisting of the amino acid sequenceat amino acid positions 117 to 128 shown in SEQ ID NO: 29, and CDRL1consisting of the amino acid sequence at amino acid positions 44 to 54shown in SEQ ID NO: 31, CDRL2 consisting of the amino acid sequence atamino acid positions 70 to 76 shown in SEQ ID NO: 31 and CDRL3consisting of the amino acid sequence at amino acid positions 109 to 117shown in SEQ ID NO:
 31. 8. The antibody according to claim 1, which has:(1) a heavy chain variable region consisting of the amino acid sequenceat amino acid positions 1 to 118 shown in SEQ ID NO: 2, and a lightchain variable region consisting of the amino acid sequence at aminoacid positions 1 to 112 shown in SEQ ID NO: 3, (2) a heavy chainvariable region consisting of the amino acid sequence at amino acidpositions 1 to 123 shown in SEQ ID NO: 4, and a light chain variableregion consisting of the amino acid sequence at amino acid positions 1to 111 shown in SEQ ID NO: 5, (3) a heavy chain variable regionconsisting of the amino acid sequence at amino acid positions 20 to 136shown in SEQ ID NO: 25, and a light chain variable region consisting ofthe amino acid sequence at amino acid positions 21 to 129 shown in SEQID NO: 27, or (4) a heavy chain variable region consisting of the aminoacid sequence at amino acid positions 20 to 139 shown in SEQ ID NO: 29,and a light chain variable region consisting of the amino acid sequenceat amino acid positions 21 to 129 shown in SEQ ID NO:
 31. 9. Theantibody according to claim 1, wherein the constant region is ahuman-derived constant region.
 10. The antibody according to claim 1,which has: (1) a heavy chain consisting of the amino acid sequence shownin SEQ ID NO: 2, and a light chain consisting of the amino acid sequenceshown in SEQ ID NO: 3, (2) a heavy chain consisting of the amino acidsequence shown in SEQ ID NO: 4, and a light chain consisting of theamino acid sequence shown in SEQ ID NO: 5, (3) a heavy chain consistingof the amino acid sequence at amino acid positions 20 to 466 shown inSEQ ID NO: 25, and a light chain consisting of the amino acid sequenceat amino acid positions 21 to 234 shown in SEQ ID NO: 27, or (4) a heavychain consisting of the amino acid sequence at amino acid positions 20to 469 shown in SEQ ID NO: 29, and a light chain consisting of the aminoacid sequence at amino acid positions 21 to 234 shown in SEQ ID NO: 31.11. The antibody according to claim 1, which is humanized.
 12. Theantibody according to claim 11, which has: a heavy chain variable regionconsisting of an amino acid sequence selected from the group consistingof: (a) the amino acid sequence at amino acid positions 20 to 136 shownin SEQ ID NO: 33, (b) the amino acid sequence at amino acid positions 20to 136 shown in SEQ ID NO: 35, (c) the amino acid sequence at amino acidpositions 20 to 139 shown in SEQ ID NO: 41, (d) an amino acid sequencehaving homology of at least 95% or more to the sequence of a frameworkregion other than at each CDR sequence in the sequences of (a) to (c),and (e) an amino acid sequence comprising a deletion, substitution oraddition of one or several amino acids in the sequence of a frameworkregion other than at each CDR sequence in the sequences of (a) to (c),and a light chain variable region consisting of an amino acid sequenceselected from the group consisting of: (f) the amino acid sequence atamino acid positions 21 to 129 shown in SEQ ID NO: 37, (g) the aminoacid sequence at amino acid positions 21 to 129 shown in SEQ ID NO: 39,(h) the amino acid sequence at amino acid positions 21 to 129 shown inSEQ ID NO: 43, (i) an amino acid sequence having homology of at least95% or more to the sequence of a framework region other than at each CDRsequence in the sequences of (f) to (h), and (j) an amino acid sequencecomprising a deletion, substitution or addition of one or several aminoacids in the sequence of a framework region other than at each CDRsequence in the sequences of (f) to (h).
 13. The antibody according toclaim 11, which has: (1) a heavy chain variable region consisting of theamino acid sequence at amino acid positions 20 to 136 shown in SEQ IDNO: 33, and a light chain variable region consisting of the amino acidsequence at amino acid positions 21 to 129 shown in SEQ ID NO: 37, (2) aheavy chain variable region consisting of the amino acid sequence atamino acid positions 20 to 136 shown in SEQ ID NO: 35, and a light chainvariable region consisting of the amino acid sequence at amino acidpositions 21 to 129 shown in SEQ ID NO: 39, or (3) a heavy chainvariable region consisting of the amino acid sequence at amino acidpositions 21 to 139 shown in SEQ ID NO: 41, and a light chain variableregion consisting of the amino acid sequence at amino acid positions 21to 129 shown in SEQ ID NO:
 43. 14. The antibody according to claim 11,which has: (1) a heavy chain selected from the group consisting of aheavy chain having the amino acid sequence at amino acid positions 20 to466 shown in SEQ ID NO: 33, a heavy chain having the amino acid sequenceat amino acid positions 20 to 466 shown in SEQ ID NO: 35, and a heavychain having the amino acid sequence at amino acid positions 20 to 469shown in SEQ ID NO: 41, and (2) a light chain selected from the groupconsisting of a light chain having the amino acid sequence at amino acidpositions 21 to 234 shown in SEQ ID NO: 37, a light chain having theamino acid sequence at amino acid positions 21 to 234 shown in SEQ IDNO: 39, and a light chain having the amino acid sequence at amino acidpositions 21 to 234 shown in SEQ ID NO:
 43. 15. The antibody accordingto claim 11, which has: (1) a heavy chain having the amino acid sequenceat amino acid positions 20 to 466 shown in SEQ ID NO: 33, and a lightchain having the amino acid sequence at amino acid positions 21 to 234shown in SEQ ID NO: 37, (2) a heavy chain having the amino acid sequenceat amino acid positions 20 to 466 shown in SEQ ID NO: 35, and a lightchain having the amino acid sequence at amino acid positions 21 to 234shown in SEQ ID NO: 39, or (3) a heavy chain having the amino acidsequence at amino acid positions 20 to 469 shown in SEQ ID NO: 41, and alight chain having the amino acid sequence at amino acid positions 21 to234 shown in SEQ ID NO:
 43. 16. A polynucleotide encoding the antibodyaccording to claim
 1. 17. The polynucleotide according to claim 16,which has: (1) a polynucleotide of CDRH1 consisting of the nucleotidesequence at nucleotide positions 76 to 105 shown in SEQ ID NO: 6, apolynucleotide of CDRH2 consisting of the nucleotide sequence atnucleotide positions 148 to 198 shown in SEQ ID NO: 6 and apolynucleotide of CDRH3 consisting of the nucleotide sequence atnucleotide positions 295 to 321 shown in SEQ ID NO: 6, and apolynucleotide of CDRL1 consisting of the nucleotide sequence atnucleotide positions 67 to 108 shown in SEQ ID NO: 7, a polynucleotideof CDRL2 consisting of the nucleotide sequence at nucleotide positions154 to 174 shown in SEQ ID NO: 7 and a polynucleotide of CDRL3consisting of the nucleotide sequence at nucleotide positions 271 to 303shown in SEQ ID NO: 7, (2) a polynucleotide of CDRH1 consisting of thenucleotide sequence at nucleotide positions 76 to 105 shown in SEQ IDNO: 8, a polynucleotide of CDRH2 consisting of the nucleotide sequenceat nucleotide positions 148 to 198 shown in SEQ ID NO: 8 and apolynucleotide of CDRH3 consisting of the nucleotide sequence atnucleotide positions 295 to 336 shown in SEQ ID NO: 8, and apolynucleotide of CDRL1 consisting of the nucleotide sequence atnucleotide positions 67 to 108 shown in SEQ ID NO: 9, a polynucleotideof CDRL2 consisting of the nucleotide sequence at nucleotide positions154 to 174 shown in SEQ ID NO: 9 and a polynucleotide of CDRL3consisting of the nucleotide sequence at nucleotide positions 271 to 300shown in SEQ ID NO: 9, (3) a polynucleotide of CDRH1 consisting of thenucleotide sequence at nucleotide positions 133 to 162 shown in SEQ IDNO: 24, a polynucleotide of CDRH2 consisting of the nucleotide sequenceat nucleotide positions 205 to 234 shown in SEQ ID NO: 24 and apolynucleotide of CDRH3 consisting of the nucleotide sequence atnucleotide positions 352 to 375 shown in SEQ ID NO: 24, and apolynucleotide of CDRL1 consisting of the nucleotide sequence atnucleotide positions 130 to 162 shown in SEQ ID NO: 26, a polynucleotideof CDRL2 consisting of the nucleotide sequence at nucleotide positions208 to 228 shown in SEQ ID NO: 26 and a polynucleotide of CDRL3consisting of the nucleotide sequence at nucleotide positions 325 to 351shown in SEQ ID NO: 26, or (4) a polynucleotide of CDRH1 consisting ofthe nucleotide sequence at nucleotide positions 133 to 162 shown in SEQID NO: 28, a polynucleotide of CDRH2 consisting of the nucleotidesequence at nucleotide positions 205 to 231 shown in SEQ ID NO: 28 and apolynucleotide of CDRH3 consisting of the nucleotide sequence atnucleotide positions 349 to 384 shown in SEQ ID NO: 28, and apolynucleotide of CDRL1 consisting of the nucleotide sequence atnucleotide positions 130 to 162 shown in SEQ ID NO: 30, a polynucleotideof CDRL2 consisting of the nucleotide sequence at nucleotide positions208 to 228 shown in SEQ ID NO: 30 and a polynucleotide of CDRL3consisting of the nucleotide sequence at nucleotide positions 325 to 351shown in SEQ ID NO:
 30. 18. The polynucleotide according to claim 16,which has: (1) a polynucleotide of a heavy chain variable regionconsisting of the nucleotide sequence at nucleotide positions 1 to 354shown in SEQ ID NO: 6, and a polynucleotide of a light chain variableregion consisting of the nucleotide sequence at nucleotide positions 1to 336 shown in SEQ ID NO: 7, (2) a polynucleotide of a heavy chainvariable region consisting of the nucleotide sequence at nucleotidepositions 1 to 369 shown in SEQ ID NO: 8, and a polynucleotide of alight chain variable region consisting of the nucleotide sequence atnucleotide positions 1 to 333 shown in SEQ ID NO: 9, (3) apolynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 24, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 26, or (4) a polynucleotide of a heavy chain variable regionconsisting of the nucleotide sequence at nucleotide positions 58 to 417shown in SEQ ID NO: 28, and a polynucleotide of a light chain variableregion consisting of the nucleotide sequence at nucleotide positions 61to 387 shown in SEQ ID NO:
 30. 19. The polynucleotide according to claim16, which has: (1) a polynucleotide of a heavy chain consisting of thenucleotide sequence shown in SEQ ID NO: 6, and a polynucleotide of alight chain consisting of the nucleotide sequence shown in SEQ ID NO: 7,(2) a polynucleotide of a heavy chain consisting of the nucleotidesequence shown in SEQ ID NO: 8, and a polynucleotide of a light chainconsisting of the nucleotide sequence shown in SEQ ID NO: 9, (3) apolynucleotide of a heavy chain consisting of the nucleotide sequence atnucleotide positions 58 to 1398 shown in SEQ ID NO: 24, and apolynucleotide of a light chain consisting of the nucleotide sequence atnucleotide positions 61 to 702 shown in SEQ ID NO: 26, or (4) apolynucleotide of a heavy chain consisting of the nucleotide sequence atnucleotide positions 58 to 1407 shown in SEQ ID NO: 28, and apolynucleotide of a light chain consisting of the nucleotide sequence atnucleotide positions 61 to 702 shown in SEQ ID NO:
 30. 20. Thepolynucleotide according to claim 16, which has: (1) a polynucleotide ofa heavy chain variable region selected from the group consisting of apolynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 32, a polynucleotide of a heavy chain variable region consisting ofthe nucleotide sequence at nucleotide positions 58 to 408 shown in SEQID NO: 34, and a polynucleotide of a heavy chain variable regionconsisting of the nucleotide sequence at nucleotide positions 58 to 417shown in SEQ ID NO: 40, and (2) a polynucleotide of a light chainvariable region selected from the group consisting of a polynucleotideof a light chain variable region consisting of the nucleotide sequenceat nucleotide positions 61 to 387 shown in SEQ ID NO: 36, apolynucleotide of a light chain variable region consisting of thenucleotide sequence at nucleotide positions 61 to 387 shown in SEQ IDNO: 38, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO:
 42. 21. The polynucleotide according to claim 16, which has:(1) a heavy chain variable region consisting of the nucleotide sequenceat nucleotide positions 58 to 408 shown in SEQ ID NO: 32, and a lightchain variable region consisting of the nucleotide sequence atnucleotide positions 61 to 387 shown in SEQ ID NO: 36, (2) apolynucleotide of a heavy chain variable region consisting of thenucleotide sequence at nucleotide positions 58 to 408 shown in SEQ IDNO: 34, and a polynucleotide of a light chain variable region consistingof the nucleotide sequence at nucleotide positions 61 to 387 shown inSEQ ID NO: 38, or (3) a polynucleotide of a heavy chain variable regionconsisting of the nucleotide sequence at nucleotide positions 58 to 417shown in SEQ ID NO: 40, and a polynucleotide of a light chain variableregion consisting of the nucleotide sequence at nucleotide positions 61to 387 shown in SEQ ID NO:
 42. 22. The polynucleotide according to claim16, which has: (1) a polynucleotide of a heavy chain selected from thegroup consisting of a polynucleotide of a heavy chain consisting of thenucleotide sequence at nucleotide positions 58 to 1398 shown in SEQ IDNO: 32, a polynucleotide of a heavy chain consisting of the nucleotidesequence at nucleotide positions 58 to 1398 shown in SEQ ID NO: 34, anda polynucleotide of a heavy chain consisting of the nucleotide sequenceat nucleotide positions 58 to 1407 shown in SEQ ID NO: 40, and (2) apolynucleotide of a light chain selected from the group consisting of apolynucleotide of a light chain consisting of the nucleotide sequence atnucleotide positions 61 to 702 shown in SEQ ID NO: 36, a polynucleotideof a light chain consisting of the nucleotide sequence at nucleotidepositions 61 to 702 shown in SEQ ID NO: 38, and a polynucleotide of alight chain consisting of the nucleotide sequence at nucleotidepositions 61 to 702 shown in SEQ ID NO:
 42. 23. The polynucleotideaccording to claim 16, which has: (1) a polynucleotide of a heavy chainconsisting of the nucleotide sequence at nucleotide positions 58 to 1398shown in SEQ ID NO: 32, and a polynucleotide of a light chain consistingof the nucleotide sequence at nucleotide positions 61 to 702 shown inSEQ ID NO: 36, (2) a polynucleotide of a heavy chain consisting of thenucleotide sequence at nucleotide positions 58 to 1398 shown in SEQ IDNO: 34, and a polynucleotide of a light chain consisting of thenucleotide sequence at nucleotide positions 61 to 702 shown in SEQ IDNO: 38, or (3) a polynucleotide of a heavy chain consisting of thenucleotide sequence at nucleotide positions 58 to 1407 shown in SEQ IDNO: 40, and a polynucleotide of a light chain consisting of thenucleotide sequence at nucleotide positions 61 to 702 shown in SEQ IDNO:
 42. 24. An expression vector comprising the polynucleotide accordingto claim
 16. 25. Host cells transformed with the expression vectoraccording to claim
 24. 26. A method for producing an antibody ofinterest or a fragment thereof, which comprises a step of culturing thehost cells according to claim 25, and a step of collecting an antibodyof interest from the culture obtained by the aforementioned step.
 27. Anantibody obtained by the production method according to claim
 26. 28.The antibody according to claim 1, comprising one or two or moremodifications selected from the group consisting of N-linkedglycosylation, O-linked glycosylation, N-terminal processing, C-terminalprocessing, deamidation, isomerization of aspartic acid, oxidation ofmethionine, addition of a methionine residue to the N-terminus,amidation of a proline residue, and a heavy chain comprising a deletionof one or two amino acids at the carboxyl terminus.
 29. The antibodyaccording to claim 28, wherein one or two amino acids are deleted at thecarboxyl terminus of a heavy chain thereof.
 30. The antibody accordingto claim 29, wherein one amino acid is deleted at each of the carboxyltermini of both of the heavy chains thereof.
 31. The antibody accordingto claim 28, wherein a proline residue at the carboxyl terminus of aheavy chain thereof is further amidated.
 32. The antibody according toclaim 1, wherein sugar chain modification is regulated in order toenhance antibody-dependent cellular cytotoxicity.
 33. A pharmaceuticalcomposition comprising at least one of the antibodies according toclaim
 1. 34. The pharmaceutical composition according to claim 33, whichis for use in tumor therapy.
 35. The pharmaceutical compositionaccording to claim 34, wherein the tumor is a cancer.
 36. Thepharmaceutical composition according to claim 35, wherein the cancer islung cancer, kidney cancer, urothelial cancer, colon cancer, prostatecancer, glioblastoma multiforme, ovarian cancer, pancreatic cancer,breast cancer, melanoma, liver cancer, bladder cancer, stomach cancer,esophageal cancer, or blood cancer.
 37. A method for treating a tumor,which comprises administering at least one of the antibodies accordingto claim 1 to an individual.
 38. The treatment method according to claim37, wherein the tumor is a cancer.
 39. The treatment method according toclaim 38, wherein the cancer is lung cancer, kidney cancer, urothelialcancer, colon cancer, prostate cancer, glioblastoma multiforme, ovariancancer, pancreatic cancer, breast cancer, melanoma, liver cancer,bladder cancer, stomach cancer, esophageal cancer, or blood cancer.